Techniques for mobility mode selection in uplink-based and downlink-based mobility

ABSTRACT

Various aspects described herein relate to techniques for mobility mode selection in uplink-based and downlink-based mobility in wireless communications systems. In an aspect, a method for wireless communications may include determining that a user equipment (UE) is operating in a first mobility mode, determining whether the UE satisfies at least one condition associated with mobility of the UE for mobility mode selection, and selecting a second mobility mode based on a determination that the UE satisfies the at least one condition, wherein each of the first mobility mode and the second mobility mode is an uplink mobility mode or a downlink mobility mode. The techniques described herein may apply to different communications technologies, including the 5th Generation (5G) New Radio (NR) communications technology.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/001,527, entitled “TECHNIQUES FOR MOBILITY MODE SELECTION INUPLINK-BASED AND DOWNLINK-BASED MOBILITY” and filed on Jun. 6, 2018,which is a continuation of U.S. application Ser. No. 15/462,574,entitled “TECHNIQUES FOR MOBILITY MODE SELECTION IN UPLINK-BASED ANDDOWNLINK-BASED MOBILITY” and filed on Mar. 17, 2017, which claims thebenefits of U.S. Provisional Application Ser. No. 62/399,885, entitled“TECHNIQUES FOR MOBILITY MODE SELECTION IN UPLINK-BASED ANDDOWNLINK-BASED MOBILITY” and filed on Sep. 26, 2016, and U.S.Provisional Application No. 62/402,833, entitled “METHOD AND APPARATUSOF MOBILITY MODE SWITCH IN UPLINK BASED MOBILITY” and filed on Sep. 30,2016, all of which are expressly incorporated by reference herein intheir entirety.

BACKGROUND

Aspects of the present disclosure relate generally to wirelesscommunications systems, and more particularly, to techniques formobility mode selection in uplink-based and downlink-based mobility inwireless communications systems (e.g., 5G New Radio).

Wireless communications systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communications systems may employmultiple-access technologies capable of supporting communications withmultiple users by sharing available system resources (e.g., time,frequency, power, and/or spectrum). Examples of such multiple-accesstechnologies include code division multiple access (CDMA) systems, timedivision multiple access (TDMA) systems, frequency division multipleaccess (FDMA) systems, orthogonal frequency division multiple access(OFDMA) systems, single-carrier frequency division multiple access(SC-FDMA) systems, and time division synchronous code division multipleaccess (TD-SCDMA).

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example telecommunication standardis Long Term Evolution (LTE) or LTE-Advanced (LTE-A). However, althoughnewer multiple access systems, such as an LTE or LTE-A system, deliverfaster data throughput than older technologies, such increased downlinkrates have triggered a greater demand for higher-bandwidth content, suchas high-resolution graphics and video, for use on or with mobiledevices. As such, demand for bandwidth, higher data rates, bettertransmission quality as well as better spectrum utilization, and lowerlatency on wireless communications systems continues to increase.

The 5th Generation (5G) New Radio (NR) communications technology, usedin a wide range of spectrum, is envisaged to expand and support diverseusage scenarios and applications with respect to current mobile networkgenerations. In an aspect, 5G NR communications technology includes, forexample: enhanced mobile broadband (eMBB) addressing human-centric usecases for access to multimedia content, services and data;ultra-reliable low-latency communications (URLLC) with strictrequirements, especially in terms of latency and reliability; andmassive machine type communications (mMTC) for a very large number ofconnected devices and typically transmitting a relatively low volume ofnon-delay-sensitive information.

In addition, as the demand for mobile broadband access continues toincrease, there exists a need for further improvements in 5Gcommunications technology and beyond. Preferably, these improvementsshould be applicable to other multi-access technologies and thetelecommunication standards that employ these technologies.

Accordingly, due to the requirements for increased data rates, reducedlatency, power savings, and better resource utilization, new approachesmay be desirable to improve the system design and reliability. Inaddition, there are needs to allow for an uplink mobility mode and/or adownlink mobility mode to address mobility and/or different channelconditions that impact a wireless communications system. In this case,new or improved mobility mode selection or switch procedures forinter-zone mobility and/or intra-zone mobility may be desired to improveuser experience in wireless communications (e.g., 5G NR).

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its purpose is to presentsome concepts of one or more aspects in a simplified form as a preludeto the more detailed description that is presented later.

According to an example, a method related to mobility mode selection fora user equipment (UE) in a wireless communications system is provided.The method includes determining that a UE is operating in a firstmobility mode; determining whether the UE satisfies at least onecondition associated with mobility of the UE for mobility modeselection; and selecting a second mobility mode based on a determinationthat the UE satisfies the at least one condition, wherein each of thefirst mobility mode and the second mobility mode is an uplink (UL)mobility mode or a downlink (DL) mobility mode.

In an aspect, an apparatus for wireless communications is provided. Theapparatus for wireless communications may include a memory configured tostore instructions; and at least one processor communicatively coupledwith the memory, wherein the at least one processor is configured toexecute the instructions to: determine that the apparatus is operatingin a first mobility mode; determine whether the apparatus satisfies atleast one condition associated with mobility of the apparatus formobility mode selection; and select a second mobility mode based on adetermination that the apparatus satisfies the at least one condition,wherein each of the first mobility mode and the second mobility mode isan uplink (UL) mobility mode or a downlink (DL) mobility mode.

In another aspect, an apparatus for wireless communication is provided.The apparatus for wireless communications may include means fordetermining that the apparatus is operating in a first mobility mode;means for determining whether the apparatus satisfies at least onecondition associated with mobility of the apparatus for mobility modeselection; and means for selecting a second mobility mode based on adetermination that the apparatus satisfies the at least one condition,wherein each of the first mobility mode and the second mobility mode isan uplink (UL) mobility mode or a downlink (DL) mobility mode.

In a further aspect, a computer-readable medium (e.g., a non-transitorycomputer-readable storage medium) is provided and includes codeexecutable by one or more processors to perform the operations ofmethods described herein. The computer-readable medium may include codeexecutable by at least one processor to: determine that a user equipment(UE) is operating in a first mobility mode; determine whether the UEsatisfies at least one condition associated with mobility of the UE formobility mode selection; and select a second mobility mode based on adetermination that the UE satisfies the at least one condition, whereineach of the first mobility mode and the second mobility mode is anuplink (UL) mobility mode or a downlink (DL) mobility mode.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to facilitate a fuller understanding of aspects describedherein, reference is now made to the accompanying drawings, in whichlike elements are referenced with like numerals. These drawings shouldnot be construed as limiting the present disclosure, but are intended tobe illustrative only.

FIG. 1 is an example of a wireless communications system including atleast one network entity in communication with at least a user equipment(UE), according to one or more of the presently described aspects;

FIG. 2 is an example of a zone of cells in a network with at least aUE-centric MAC layer, according to one or more of the presentlydescribed aspects;

FIG. 3 is a block diagram illustrating an example of a base stationconfigured to perform communication management, according to one or moreof the presently described aspects;

FIG. 4 is a block diagram illustrating an example of a UE configured toperform mobility mode selection and mobility management, according toone or more of the presently described aspects;

FIG. 5 is a call flow illustrating an example of a network initialuplink mobility mode to downlink mobility mode reconfiguration,according to one or more of the presently described aspects;

FIG. 6 is a call flow illustrating an example of a UE requested uplinkmobility mode to downlink mobility mode switch reconfiguration,according to one or more of the presently described aspects;

FIG. 7 is a call flow illustrating an example of an autonomous switchfrom uplink mobility mode to downlink mobility mode, according to one ormore of the presently described aspects;

FIG. 8 is a call flow illustrating an example of a UE requested downlinkmobility mode to uplink mobility mode reconfiguration, according to oneor more of the presently described aspects;

FIG. 9 is a call flow illustrating an example of an autonomous downlinkmobility mode to uplink mobility mode switch, according to one or moreof the presently described aspects;

FIG. 10 is a call flow illustrating an example of an uplink measurementbased intra-zone forward handover, according to one or more of thepresently described aspects;

FIG. 11 is a call flow illustrating an example of an uplink measurementbased inter-zone backward handover, according to one or more of thepresently described aspects;

FIG. 12 is a call flow illustrating an example of a downlink measurementbased inter-zone mobility for backward handover, according to one ormore of the presently described aspects;

FIG. 13 is a call flow illustrating an example of a downlink measurementbased inter-zone mobility, according to one or more of the presentlydescribed aspects;

FIG. 14 is a block diagram illustrating an example of a structure ofsynchronization channels for uplink based mobility, according to one ormore of the presently described aspects;

FIG. 15 is a block diagram of an example of radio resource control (RRC)states and RRC state transitions of a UE, according to one or more ofthe presently described aspects.

FIG. 16A is a first example of signal exchanges between a UE and anAccess Node (AN) for mobility mode selection and management, accordingto one or more of the presently described aspects.

FIG. 16B is a second example of signal exchanges between a UE and anAccess Node (AN) for mobility mode selection and management, accordingto one or more of the presently described aspects.

FIG. 17 is a flowchart of an example method of mobility mode selectionand management, according to one or more of the presently describedaspects;

FIG. 18 is a flowchart of an example method of mobility mode managementfor inter-zone mobility, according to one or more of the presentlydescribed aspects;

FIG. 19 is a flowchart of an example method of mobility mode selectionand management for a UE, according to one or more of the presentlydescribed aspects; and

FIG. 20 is a flowchart of an example method of mobility mode selectionand management for a network entity (e.g., a base station), according toone or more of the presently described aspects.

DETAILED DESCRIPTION

Some conventional wireless communications systems, such as a long termevolution (LTE) system or a high-speed packet access (HSPA) system, mayuse downlink-based mobility procedures to change a serving cell of auser equipment (UE). In an example of a downlink-based mobilityprocedure, the UE may measure downlink signals from a serving celland/or one or more neighbor cells. The UE and/or the network may thendetermine whether the UE may change cells based on the quality of thedownlink signals. In some cases, a downlink-based mobility procedure maynot be ideal for a UE. For example, for downlink-based mobility, the UEmay periodically perform cell search and measurements based on referencesignals transmitted by the network, some of the processing requirementsfor the handover decisions are shifted to the UE. As a result, the UE(e.g., a smart phone operating on limited battery supply) may expendgreater processing time, and thus require increased power consumption.

In some aspects, a wireless communications (e.g., 5G NR) may useuplink-based mobility procedure to alleviate power requirement concernsassociated with the downlink-based mobility procedures. In uplink-basedmobility procedures, one or more base stations in the network maymeasure a signal transmitted by the UE. In an aspect, the network maydetermine whether to change the serving cell for the UE.

Similar downlink-based and uplink-based mobility procedures may beadopted for zone mobility where a UE may transition from a serving zoneto a target zone based on the measured signal quality between the UE anda serving base station. A zone may refer to a group or combination ofcells that act together and are synchronized. Thus, a zone may include aplurality of cells operating on the same frequency and/or with the sametiming, etc., such that a handover from one cell to another within thezone may be controlled by the network and be transparent to the UE. Insome conventional systems, for inter-zone mobility (e.g., UEtransitioning from a first zone to a second zone), triggered by eitherdownlink-based mobility procedures or uplink-based mobility procedures,a UE is required to perform a blind zone search. In an aspect, a blindzone search may require the UE to measure and compare the signalqualities of one or more (e.g., all) available zones prior to selectinga target zone for transition. Such expansive blind search requirementsfor inter-zone mobility may, in some cases, be unnecessary and also mayadversely impact the UE power consumption.

In a wireless communications system (e.g., a 5G NR system), a networkmay support various mobility procedures that may be beneficial invarious conditions (e.g., a speed of a UE, channel condition(s), alocation of the UE, and/or a radio resource control (RRC) state of theUE). For example, a UE may move at a high speed, a low speed, or bestationary. In another example, the UE may be at a cell edge or a zoneedge. Additionally, in some examples, a UE may operate in one or moreRRC states, and may transition from one RRC state to another RRC state.As such, to improve system reliability and the performance of thewireless communications system, new or improved mobility mode selectionprocedures or schemes may be desirable to help the UE and/or the networkto select, switch, or operate in an appropriate mobility mode (e.g.,downlink-based mobility or uplink-based mobility) in differentconditions.

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known components are shown in blockdiagram form in order to avoid obscuring such concepts.

Several aspects of telecommunications systems will now be presented withreference to various apparatus and methods. These apparatus and methodswill be described in the following detailed description and illustratedin the accompanying drawings by various blocks, modules, components,circuits, steps, processes, algorithms, etc. (collectively referred toas “elements”). These elements may be implemented using electronichardware, computer software, or any combination thereof. Whether suchelements are implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented with a “processing system”that includes one or more processors. Examples of processors includemicroprocessors, microcontrollers, digital signal processors (DSPs),field programmable gate arrays (FPGAs), programmable logic devices(PLDs), state machines, gated logic, discrete hardware circuits, andother suitable hardware configured to perform the various functionalitydescribed throughout this disclosure. One or more processors in theprocessing system may execute software. Software shall be construedbroadly to mean instructions, instruction sets, code, code segments,program code, programs, subprograms, software modules, applications,software applications, software packages, routines, subroutines,objects, executables, threads of execution, procedures, functions, etc.,whether referred to as software, firmware, middleware, microcode,hardware description language, or otherwise.

Accordingly, in one or more aspects, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on or encoded asone or more instructions or code on a computer-readable medium.Computer-readable media includes computer storage media. Storage mediamay be any available media that can be accessed by a computer. By way ofexample, and not limitation, such computer-readable media can compriseRAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic diskstorage or other magnetic storage devices, or any other medium that canbe used to carry or store desired program code in the form ofinstructions or data structures and that can be accessed by a computer.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), and floppy disk where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above should also be includedwithin the scope of computer-readable media. In some aspects, thecomputer-readable media may be non-transitory or include anon-transitory computer-readable storage medium.

Described herein are various aspects related to a wirelesscommunications system (e.g., 5G NR system), in particular, techniquesfor mobility mode selection in uplink (UL)-based and/or downlink(DL)-based mobility. In some aspects, a mobile device (e.g., a UE) mayselect and/or operate in a different mobility mode to improve theperformance of wireless communications using the present disclosure ofmobility mode selection procedure. In some examples, a network (or anetwork entity in a network) may support both UL-based and DL-basedmobility simultaneously. In some examples, a UL mobility mode and a DLmobility mode may be adaptively selected by a UE and/or a network. In anaspect, DL-based mobility is used in some conventional wirelesscommunications systems (e.g., the 3rd Generation (3G) network and/or the4th Generation (4G) network) and may include a network sending referencesignals (RS), a UE performing cell search and/or measurements, and/orthe network making decisions for cell (re)selections. In another aspect,UL-based mobility may include a UE sending RS and the network performingUE search and/or measurements. In some examples, UL-based mobility maybe used in some conventional wireless communications systems (e.g., 3Gor 4G system), or a future wireless communications system (e.g., 5G NRsystem).

In some aspects, UL-based mobility may enable more flexible powerconsumption-to-reliability tradeoff for a UE, faster layer 1 (LI)handshake to provide both the UE and the network with improved and/ortimely information on a specific channel, and/or improved mobilitytracking when more antennas are available at the network. In someexamples, UL-based mobility may have benefits when a UE is at highmobility and/or with a poor channel condition. In particular, forexample, using UL-based mobility may reduce UE power consumptions,reduce paging miss-and-call setup delay, reduce network resource (RS andpaging) utilization, and/or reduce handover failure rate. On the otherhand, for example, DL-based mobility may have benefits when a UE is atlow mobility and/or benign/good channel conditions.

Generally, conventional technologies utilize a DL-based mobilityprocedure regardless of the UE mobility state. For example, in a 5G NRsystem, a network may support various mobility procedures that may bebeneficial in various conditions. A DL mobility mode may involve the UEmeasuring signals from one or more cells and the UE or network selectinga serving cell based on the UE measurements. A UL mobility mode mayinvolve the UE transmitting one or more UL measurement indicationsignals that the network uses to determine a serving cell for the UE. InUL-based mobility, cells may be organized into synchronized groupsreferred to herein as zones. The cells within a zone may form a singlefrequency network (SFN). One cell within the zone may be selected as theserving cell for a UE, and the UE may not need to be aware of which cellwithin the zone is the serving cell. Instead, the UE may treat the zoneas a serving zone. In some examples, UL-based mobility procedures forintra-zone mobility and inter-zone mobility may be different.

In some aspects related to UL-based mobility, a UE may be in a zonewhich includes a collection of tightly synchronized cells. In someexamples, the zone may be a super cell with a plurality of synchronizedcells. In an aspect, intra-zone mobility may be transparent to UE(s). Inan example of intra-zone mobility, a UE may send one or more UL mobilityreference signals (e.g., Physical Uplink Measurement Indication Channel(PUMICH) or Physical Uplink Measurement Reference Signal (PUMRS)) formobility tracking at the network. In response, the network may decodethe received one or more reference signals and acknowledge (ACK) ULmobility reference signal(s) and/or signaling paging indicator(s)received from the UE. For example, the network may send a PhysicalKeep-Alive Channel (PKACH) for acknowledging UL mobility referencesignal(s) and/or signaling paging indicator(s). In some examples, thePKACH may be sent or transmitted using a physical (PHY) layer procedure.In an aspect of intra-zone mobility, the network may autonomously selecta serving cell or a transmission/reception point (TRP), or cells (e.g.,target cells) or TRPs to send PKACH to one or more UEs. For example, thenetwork may autonomously select one or more serving cells for one ormore UEs when the one or more UEs are in a high-speed train.

In accordance with various aspects of the present disclosure, the PUMICHmay include the same UE identification (ID) as the UE-ID used in thesource zone, a new UE-ID which may be assigned by the target zone andsent over an interface by the source zone to the target zone, or aninitial access UE-ID which may be used when a UE accesses a zone for thefirst time. In some aspects, the initial access UE-ID may be eitherrandomly generated or signaled by system information or hard-coded in aspecification.

In some aspects related to inter-zone mobility, a UE may performinter-zone handover when one or more conditions is/are satisfied. Forexample, inter-zone mobility may be triggered when one or more (e.g., aset of) mobility trigger conditions is/are satisfied (e.g., signalquality of the channel falling below a threshold). In some examples,inter-zone mobility may be triggered by the UE based on a UL-basedmobility procedure. However, prior to performing a cell/zone searchand/or a cell/zone reselection, the UE may transition to the DL-basedmobility procedures to verify the authenticity of the inter-zonemobility trigger conditions and for zone/cell ranking. In an aspect,upon verification and initiating a transition to the target cell orzone, the UE may return to performing UL-based mobility procedures inorder to minimize the processing requirements of the UE.

To support UL-based mobility, the network may provide one or moresynchronization signals and reference signals. The one or more signalsprovided by an individual cell may depend on the mobility modessupported by the network or the individual cell. Generally, a cell thatsupports DL-based mobility may transmit a cell-specific synchronization(SYNC) signal so that a UE may discover one or more neighbor cells. Acell that supports UL-based mobility may transmit at least azone-specific measurement reference signal so that a UE may measure thezone, which may be identified by a serving cell. In an aspect, a cellthat supports UL-based mobility may also transmit a zone-specific SYNCsignal so that the UE may discover the zone, for example, as a neighborzone for inter-zone mobility.

As discussed above, in some conventional systems, for inter-zonemobility, a UE may be required to perform a blind zone search. A blindzone search may require the UE to measure the signal qualities of one ormore (e.g., all) available zones prior to selecting a target zone fortransition, and thus waste valuable resources (e.g., power andprocessing time). The present disclosure provides techniques thatminimize the blind search requirements for the UE during inter-zonemobility by configuring the network to transmit a neighbor list (e.g., aneighbor zone list and/or a neighbor cell list) to the UE thatidentifies a subset of neighbor zones and/or neighbor cells from a listof all available zones and cells that the UE may consider. Byconsidering only a subset of zones and cell identified in the neighborlist, the UE may search for SYNC signals corresponding to only theidentified zones and/or cells included in the neighbor list, whiledisregarding the SYNC signals from other zones or cells. As such, the UEmay limit the number of neighbor zones and/or cells for which the UEmeasures and compares the power difference (e.g., power differencebetween the serving zone/cell and potential target neighbor zone/cell)in verifying inter-zone mobility trigger conditions, and therebyconserve power. In some examples, in addition or alternative to theneighbor zone list and/or neighbor cell list, the neighbor list mayinclude information associated with neighbor radio access technologies(RATs), neighbor frequency information, or a combination of one or moreof the above neighbor information.

Additionally or alternatively, aspects of the present disclosure providetechniques for dynamically switching mobility mode (e.g., DL-basedmobility or UL-based mobility) of the UE based on one or moreconditions. For example, if a UE moves at a high speed (e.g., the UE isin a car), to be more efficient, the UE may be configured to switch to aUL mobility mode in order to take advantage of more robust mobilityperformance and improved paging performance. In contrast, if the UE isstationary or slowly moving (e.g., a user is walking with the UE), thenthe aspects of the present disclosure may switch the UE to DL mobilitymode for improved efficiency. In further examples, UEs located at a zoneedge, may be better served by DL mobility mode than UL mobility modebecause in DL mobility mode, the UE may compare more than one DLreference signals coming from different access nodes or TRPs. In such asituation, the UE may determine the mobility of the UE without theinterworking between the source and the target base stations, and thusreduce the network complexity.

Therefore, in some aspects, the UE may dynamically switch from a ULmobility mode to a DL mobility mode if the UE is located at the zoneedge (e.g., when UE is moving into another zone coverage and/or a cellcoverage). Additionally or alternatively, the UE may switch from a ULmobility mode to a DL mobility mode if the UE mobility speed is lessthan a mobility threshold. In contrast, the UE may also dynamicallyswitch from a DL mobility mode to a UL mobility mode if, for example,the UE mobility speed exceeds the mobility threshold. In some aspects,the UE speed may be estimated based on the Doppler estimation, number ofserving TRPs that change in a certain time period, or speed given by theother mean such as a GPS or a speed sensor embedded in the UE.

In some aspects as discussed above, a UE may operate in one or moreradio resource control (RRC) states, and may transition from one RRCstate to another RRC state. These RRC states may be included in twomodes, a Connected Mode and an Idle Mode. In some examples, a ConnectedMode may include, but not limited to, an RRC-DEDICATED state and/or anRRC-COMMON state. In some examples, an Idle Mode may include, but notlimited to, a REACHABLE-IDLE state (or an RRC-IDLE state) and/or a powersaving mode. In an aspect, when a UE is in an RRC-IDLE state, there maybe no UE context in a radio access network (RAN), no assigned airinterface resources for the UE, and the UE may only transmit and receivesmall data. In another aspect, when a UE is in a power saving mode,there may be no UE context in the RAN, no assigned air interfaceresources for the UE, and the UE has no data transmissions orreceptions. In an aspect, when a UE is in an RRC-COMMON state, there maybe UE context in a RAN, no assigned air interface resources for the UE,and the UE may only transmit and receive small data. In another aspect,when a UE is in an RRC-DEDICATED state, a RAN may have the UE context,the UE may have been assigned air interface resources, and the UE maytransmit and receive any data.

The present disclosure includes aspects that address mobility modeselection procedures for a UE. In some implementations of the presentdisclosure, the UE may operate in one RRC state or the UE may transitionfrom one RRC state to another RRC state. For example, when the UE is inan RRC-IDLE state, the UE may select or operate in DL mobility mode.When the UE is in an RRC-COMMON state or an RRC-DEDICATED state, the UEmay select or operate in DL mobility mode or in UL mobility mode. Insome examples, the UE may select or operate in only one mobility mode,either DL mobility mode or UL mobility mode. In some examples, a UE mayperform either UL-based or DL-based mobility at a given time. Forinstance, the UE may perform DL-based mobility when the UE is in lowmobility and/or benign/good channel conditions, and/or perform UL-basedmobility when the UE is in high mobility and/or poor channel conditions.As such, a mobility mode selection procedure may be needed for the UE toselect or operate in an appropriate mobility mode. In some examples, thenetwork may have capability of supporting both UL-based and DL-basedmobility simultaneously or adaptively. For example, in an aspect, thenetwork or a network entity may support both UL-based mobility andDL-based mobility at the same time. In another aspect, the network orthe network entity may select, choose or determine a UL-based mobilityor a DL-based mobility based on the information at the network or thenetwork entity or received from one or more UEs.

In some implementations of the present disclosure, mobility modeselection may depend on side information at UE or at network. The sideinformation may include, for example, a speed of the UE, signalmeasurements, locations, etc. In other implementations of the presentdisclosure, one or more parameters related to mobility mode selection(e.g., a speed threshold) may be signaled from the network to one ormore UEs in one or more Minimum System Information Blocks (MSIB).

According to the present disclosure, some examples relate to selecting amobility mode when a UE is transitioning from an RRC-IDLE state to anRRC-DEDICATED state. In one example implementation, a UE may predict apreferred mobility mode (e.g., based on measurements and/or identifiedinformation) and include a mobility mode recommendation in PUSCHcarrying message 3 (e.g., MSG3) of a random access procedure. In anaspect, for example, the network may send a mobility mode configurationfor the UE in PDCCH/PDSCH carrying message 4 (e.g., MSG4) of a randomaccess procedure, in response to the received mobility moderecommendation. In another example implementation, the UE may continueoperating or performing the mobility mode (e.g., DL mobility mode) whichis being used currently in the RRC-IDLE state.

Additionally, according to the present disclosure, some examples relateto selecting a mobility mode when a UE is in an RRC-DEDICATED state. Inone example implementation, the UE and the network may handshake toselect the mobility mode through dedicated RRC messages. In some otherexample implementations, the UE and the network may handshake or uselayer procedures at an L1 layer (e.g., physical layer) or at an L2 layer(e.g., a media access control (MAC) layer) to select the mobility mode(e.g., UL-based or DL mobility mode).

According to the present disclosure, some examples relate to selecting amobility mode when a UE is transitioning from an RRC-DEDICATED state toan RRC-COMMON state. In one example implementation, the UE may continueoperating or performing the mobility mode (e.g., UL-based or DL mobilitymode) which is being used in the RRC-DEDICATED state. In some otherimplementations, a mobility mode switching may be performed. Forexample, the mobility mode switching may be part of an RRCreconfiguration procedure (e.g., using RRC reconfiguration message(s)).

Additionally, according to the present disclosure, some examples relateto selecting a mobility mode when a UE is transitioning from anRRC-COMMON state to an RRC-DEDICATED state. In one exampleimplementation, the UE may continue operating or performing the mobilitymode (e.g., UL-based or DL mobility mode) which is being used in theRRC-COMMON state. In another example implementation related to aUE-driven mobility mode switching, the UE may initiate the mobility modeswitching. For example, the UE-driven mobility mode switching may bepart of an RRC connection setup request from the UE (e.g., UE sends anRRC connection setup request message). In one example implementationrelated to a network-driven mobility switching, the network (e.g., anetwork entity, a base station, or an eNB) may initiate the mobilityswitching via paging, which, for example, may be part of the network RRCconnection setup. In some examples, the network may be aware of UE'scurrent RRC state and/or a target RRC state of the UE through, forexample, RRC connection/reconnection message(s).

According to the present disclosure, some examples relate to selecting amobility mode when a UE is in an RRC-COMMON state. In one exampleimplementation related to a network-driven mobility switching, thenetwork may page the UE information or indications related to mobilitymode support change, based on side information and/or determinations atthe network (e.g., estimation of a UE speed based on a serving changefrequency).

In another example implementation related to a UE-driven mobility modeswitching (e.g., switching between a UL mobility mode and a DL mobilitymode) when the UE is in an RRC-COMMON state (e.g., in FIG. 16A), the UEmay send a mobility mode request signal or message. In some examples,the mobility mode request signal or message may include random accesschannel (RACH) information, UE identification (e.g., UE-ID), and/ormobility mode information in one bit or multiple bits (e.g., mobilitymode switching indication, a target or preferred mobility mode, orboth). In an aspect, the network may send a PKACH to acknowledgereceiving the request signal/message. The network may also send amobility mode indicator in response to the request signal/message. Inone example implementation, the mobility mode indicator may compriseone-bit information indicating whether the network accepts the mobilitymode switching request sent from the UE. In some exampleimplementations, there is no paging indicator embedded in the PKACH. Insome other example implementations, the UE may optionally send a signalto the network to inform the request completion.

In one example implementation related to a UE-driven mobility modeswitching (e.g., switching from a UL mobility mode to a DL mobilitymode) when the UE is in an RRC-COMMON state (e.g., in FIG. 16B), the UEmay send a mobility mode request signal or message. In some examples,the mobility mode request signal or message may include random accesschannel (RACH) information, UE identification (e.g., UE-ID), and/ormobility mode information in one bit or multiple bits (e.g., mobilitymode switching indication, a target or preferred mobility mode, orboth). In an aspect, the network may send a PKACH to acknowledgereceiving the request signal/message. The network may also send amobility mode indicator in response to the request signal/message. Inone example implementation, the mobility mode indicator may compriseone-bit information indicating whether the network accepts the mobilitymode switching request sent from the UE. In some exampleimplementations, the UE may be aware of one or more zones (with aplurality of cells) in the network, but not aware of a certain cell orcells for communications. In this case, the network may optionally senda Physical Cell ID Channel (PCICH) to the UE to inform or indicate oneor more cell identifications (e.g., Cell ID(s)), and the UE may use theinformed or indicated one or more cell identifications for mobility modeswitching, for example, from a UL mobility mode to a DL mobility mode.In some examples, the network may send a mobility mode configurationresponse via a Physical Downlink Control Channel (PDCCH) or a PhysicalDownlink Shared Channel (PDSCH). The UE may then decode the data orsignals received over PDCCH/PDSCH using, for example, a MobilityIndication-Radio Network Temporary Identifier (MI-RNTI), and therefore,the UE may not be need to go into or switch to an RRC-DEDICATED state todecode the received PDCCH/PDSCH.

Various aspects are now described in more detail with reference to theFIGS. 1-20. Each of the aspects described above may be performed orimplemented in connection with at least one figure in FIGS. 1-20. In thefollowing description, for purposes of explanation, numerous specificdetails are set forth in order to provide a thorough understanding ofone or more aspects. It may be evident, however, that such aspect(s) maybe practiced without these specific details. Additionally, the term“component” as used herein may be one of the parts that make up asystem, may be hardware, firmware, and/or software stored on acomputer-readable medium, and may be divided into other components.

FIG. 1 illustrates an example of a wireless communications system 100 inaccordance with various aspects of the present disclosure. The wirelesscommunications system 100 may include one or more base stations 105, oneor more UEs 115, and a core network 130. The core network 130 mayprovide user authentication, access authorization, tracking, interneprotocol (IP) connectivity, and other access, routing, or mobilityfunctions. The base stations 105 may interface with the core network 130through backhaul links 132 (e.g., 51, etc.). The base stations 105 mayperform radio configuration and scheduling for communication with theUEs 115, or may operate under the control of a base station controller(not shown). In various examples, the base stations 105 may communicate,either directly or indirectly (e.g., through core network 130), with oneanother over backhaul links 134 (e.g., X1, etc.), which may be wired orwireless communication links.

The base stations 105 may wirelessly communicate with the UEs 115 viaone or more base station antennas. Each of the base stations 105 mayprovide communication coverage for a respective geographic coverage area110. In some examples, base stations 105 may be referred to as a networkentity, transmit/receive point (TRP), a base transceiver station, aradio base station, an access point, a radio transceiver, a NodeB,eNodeB (eNB), Home NodeB, a Home eNodeB, or some other suitableterminology. The geographic coverage area 110 for a base station 105 maybe divided into sectors making up only a portion of the coverage area(not shown). The wireless communications system 100 may include basestations 105 of different types (e.g., macro or small cell basestations). There may be overlapping geographic coverage areas 110 fordifferent technologies.

In some examples, the wireless communications system 100 may be orinclude a Long Term Evolution (LTE) or LTE-Advanced (LTE-A) network. Thewireless communications system 100 may also be a next generationnetwork, such as a 5G wireless communication network. In LTE/LTE-Anetworks, the term evolved node B (eNB) may be generally used todescribe the base stations 105, while the term UE may be generally usedto describe the UEs 115. The wireless communications system 100 may be aheterogeneous LTE/LTE-A network in which different types of eNBs providecoverage for various geographical regions. For example, each eNB or basestation 105 may provide communication coverage for a macro cell, a smallcell, or other types of cell. The term “cell” is a term in the 3rdGeneration Partnership Project (3GPP) that can be used to describe abase station, a carrier or component carrier associated with a basestation, or a coverage area (e.g., sector, etc.) of a carrier or basestation, depending on context.

A macro cell may cover a relatively large geographic area (e.g., severalkilometers in radius) and may allow unrestricted access by UEs 115 withservice subscriptions with the network provider.

A small cell may include a lower-powered base station, as compared witha macro cell, that may operate in the same or different (e.g., licensed,unlicensed, etc.) frequency bands as macro cells. Small cells mayinclude pico cells, femto cells, and micro cells according to variousexamples. A pico cell, for example, may cover a small geographic areaand may allow unrestricted access by UEs 115 with service subscriptionswith the network provider. A femto cell may also cover a smallgeographic area (e.g., a home) and may provide restricted access by UEs115 having an association with the femto cell (e.g., UEs 115 in a closedsubscriber group (CSG), UEs 115 for users in the home, and the like). AneNB for a macro cell may be referred to as a macro eNB. An eNB for asmall cell may be referred to as a small cell eNB, a pico eNB, a femtoeNB, or a home eNB. An eNB may support one or multiple (e.g., two,three, four, and the like) cells (e.g., component carriers).

The communication networks that may accommodate some of the variousdisclosed examples may be packet-based networks that operate accordingto a layered protocol stack and data in the user plane may be based onthe IP. A radio link control (RLC) layer may perform packet segmentationand reassembly to communicate over logical channels. A MAC layer mayperform priority handling and multiplexing of logical channels intotransport channels. The MAC layer may also use HARQ to provideretransmission at the MAC layer to improve link efficiency. In thecontrol plane, the radio resource control (RRC) protocol layer mayprovide establishment, configuration, and maintenance of an RRCconnection between a UE 115 and the base stations 105. The RRC protocollayer may also be used for core network 130 support of radio bearers forthe user plane data. At the physical (PHY) layer, the transport channelsmay be mapped to physical channels.

The UEs 115 may be dispersed throughout the wireless communicationssystem 100, and each UE 115 may be stationary or mobile. In someaspects, a UE 115 may be referred to by those skilled in the art (aswell as interchangeably herein) as a mobile station, a subscriberstation, a mobile unit, a subscriber unit, a wireless unit, a remoteunit, a mobile device, a wireless device, a wireless communicationsdevice, a remote device, a mobile subscriber station, an accessterminal, a mobile terminal, a wireless terminal, a remote terminal, ahandset, a terminal, a user agent, a mobile client, a client, or someother suitable terminology. A UE 115 may be a cellular phone, a personaldigital assistant (PDA), a wireless modem, a wireless communicationdevice, a handheld device, a tablet computer, a laptop computer, acordless phone, a wireless local loop (WLL) station, a globalpositioning system (GPS) device, a multimedia device, a video device, adigital audio player (e.g., MP3 player), a camera, a game console, awearable computing device (e.g., a smart-watch, smart-glasses, a healthor fitness tracker, etc.), an appliance, a sensor, a vehiclecommunications system, a medical device, a vending machine, a device forthe Internet-of-Things, or any other similar functioning device. A UE115 may be able to communicate with various types of base stations andnetwork equipment including macro eNBs, small cell eNBs, relay basestations, and the like.

The wireless communication links 125 shown in wireless communicationssystem 100 may carry UL transmissions from a UE 115 to a base station105, or downlink (DL) transmissions, from a base station 105 to a UE115. The downlink transmissions may also be called forward linktransmissions while the uplink transmissions may also be called reverselink transmissions. Each wireless communication link 125 may include oneor more carriers, where each carrier may be a signal made up of multiplesub-carriers (e.g., waveform signals of different frequencies) modulatedaccording to the various radio technologies described above. Eachmodulated signal may be sent on a different sub-carrier and may carrycontrol information (e.g., reference signals, control channels, etc.),overhead information, user data, etc. The communication links 125 maytransmit bidirectional communications using frequency division duplex(FDD) (e.g., using paired spectrum resources) or time division duplex(TDD) operation (e.g., using unpaired spectrum resources). Framestructures may be defined for FDD (e.g., frame structure type 1) and TDD(e.g., frame structure type 2).

In aspects of the wireless communications system 100, base stations 105or UEs 115 may include multiple antennas for employing antenna diversityschemes to improve communication quality and reliability between basestations 105 and UEs 115. Additionally or alternatively, base stations105 or UEs 115 may employ multiple input multiple output (MIMO)techniques that may take advantage of multi-path environments totransmit multiple spatial layers carrying the same or different codeddata.

Wireless communications system 100 may support operation on multiplecells or carriers, a feature which may be referred to as carrieraggregation (CA) or multi-carrier operation. A carrier may also bereferred to as a component carrier (CC), a layer, a channel, etc. Theterms “carrier,” “component carrier,” “cell,” and “channel” may be usedinterchangeably herein. A UE 115 may be configured with multipledownlink CCs and one or more uplink CCs for carrier aggregation. Carrieraggregation may be used with both FDD and TDD component carriers.

In aspects of the wireless communications system 100, the wirelesscommunications system 100 may have a UE-centric MAC layer. On thenetwork side, the base stations 105 may broadcast a synchronization(SYNC) signal. The SYNC signal may be a unified SYNC signal that issupported by systems using a UE-centric MAC layer (UECM) (e.g., UECMnetworks) as well as systems using a network-centric or non UE-centricMAC layer (nUECM) (e.g., nUECM networks). The UEs 115 may receive theSYNC signal, acquire a timing of the network from the SYNC signal, andin response to acquiring the timing of the network, transmit a pilotsignal. The pilot signal transmitted by a UE 115 may be concurrentlyreceivable by a plurality of cells (e.g., base stations) within thenetwork. Each of the plurality of cells may measure a strength of thepilot signal, and the network (e.g., one or more of the base stations105 and/or a central node within the core network 130) may determine aserving cell for the UE 115. As the UE 115 continues to transmit a pilotsignal, the network may handover the UE 115 from one serving cell toanother, with or without informing the UE 115. System information may betransmitted to UEs 115 on-demand (e.g., in response to a UE 115transmitting a pilot signal), thus enabling the network to foregobroadcasting the system information and enabling the network to conservepower.

The SYNC signal transmitted by the base stations 105 being unified,however, may not identify a given cell, but rather may identify a zoneof multiple cells operating on the same frequency and/or with the sametiming, etc., as described further herein. There may be instances,however, where a UE 115 may benefit from knowing cell identifiers of aserving cell, a neighboring cell, etc. Accordingly, in an example, thebase stations 105 may also separately transmit one or more cell-specificsignals, such as measurement reference signals (MRS), which may bescrambled based on a cell identifier, one or more cell-specific SYNCsignals, which may be generated based on a sequence that indicates thecell identifier, etc., and UE 115 can receive the one or morecell-specific signals from one or more base stations 105 and identifycorresponding cells based at least in part on determining the cellidentifier that corresponds to the one or more cell-specific signals(e.g., based on determining an MRS scrambling code, cell-specific SYNCsignal sequence, etc.). In another example, the cell determined as theserving cell for the UE 115, as described above, may transmit the one ormore cell-specific signals (e.g., in response to the pilot signal fromthe UE 115) to facilitate serving cell discovery by the UE 115.

In some aspects of the wireless communications system 100, a basestation 105 may include a communication management component 340 formaintaining a neighbor list associated with the UE 105. The neighborlist may be either neighbor zone list identifying a subset of zones thatmay be available and near the UE 105 and/or neighbor cell listidentifying a subset of cells that may be available to the UE 105. Insome aspects, when the neighbor zone list is empty, the UE 105 may beable to deduce that only cell transition is available. In some examples,the base station 105 may transmit the neighbor list to the one or moreUEs 105 in order to aid the UEs 105 to reduce the blind zone searchperformed by the UE 105. The base station 105 may also indicate, by thecommunication management component 340, the set of supported mobilitymodes using a physical broadcast channel (PBCH). The PBCH may be azone-specific PBCH or a cell-specific PBCH. A zone-specific PBCH may besynchronously transmitted by each cell within a zone and may be the samesignal for each of the cells in the zone. The zone-specific PBCH mayinclude information applicable to all of the cells in the zone. Acell-specific PBCH may be transmitted by an individual cell and mayinclude information unique to the individual cell.

In some aspects of the wireless communications system 100, a UE 115 mayinclude a mobility management component 440 configured to performinter-zone mobility and/or intra-zone mobility in accordance withtechniques described herein. In some examples, the UE 115 may transitionbetween a set of mobility modes (e.g., DL-based mobility or UL-basedmobility) based on one or more conditions detected by the UE (e.g.,whether zone/cell transition trigger conditions have been satisfied).The UE 115, and more particularly the mobility management component 440,may be aided in limiting the number of zones and/or cells for which theUE 115 measures power difference for (e.g., comparing the powerdifference between serving zone/cell and target zone/cell) by receivinga neighbor list from the base station 105. In some examples, the basestation 105 may transmit (e.g., broadcast) the network list based on anevent trigger (e.g., if the neighbor list changes based on position ofthe UE 115 in the coverage area 110 or if one or more zone transitionconditions are satisfied). Alternatively, the network list may betransmitted by the base station 105 on a periodic basis using minimumsystem information blocks (SIBs).

In some examples, the mobility management component 440 may also beconfigured to detect a cell ID or a zone ID based on at least onedownlink signal transmitted by a cell. In an aspect, the mobilitymanagement component 440 may detect a primary synchronization signal(PSS) and a secondary synchronization signal (SSS) to determine anidentifier. In an aspect, the identifier may be a zone ID. In anotheraspect, the mobility transition component 440 may also detect acell-specific secondary synchronization signal (SSS-C). The mobilitytransition component 440 may determine a cell ID based on a combinationof the PSS, SSS, and SSS-C as described in further detail below. Themobility management component 440 may also synchronize a receiver of theUE 115 with the cell and determine a time/frequency offset.

FIG. 2 shows a diagram 200 illustrating a UECM network zone (e.g.,zone_1) having a coverage area 110-a and including at least a cell_1having a coverage area 110-b and a cell_2 having a coverage area 110-c.The UECM network zone may be a zone associated with at least a portionof the wireless communications system 100 described in FIG. 1. A zone,such as zone_1, may refer to a group or combination of cells that acttogether and are highly synchronized. Because of the coordinatedoperation of the cells in a zone, the SYNC signals are zone-specific.That is, the SYNC signals transmitted (e.g., broadcast) from a zone aretypically single-frequency network (SFN) SYNC signals. Asingle-frequency network is a broadcast network where severaltransmitters simultaneously send the same signal over the same frequencychannel.

The use of zones in 5G networks or other next generation communicationssystems may be advantageous for mobility management operations. Forexample, when in a zone, cell reselection may be transparent to a UE.The network may be responsible for cell reselection and mobility, andthe UE can be relieved from those responsibilities. Such an approach isnot only efficient for the UE, it is also efficient for the networkbecause the number of mobility messages that need to be exchanged with aUE are reduced.

The use of zones in 5G networks or other next generation communicationssystems may also enable certain applications such as massive MIMO, forexample. Massive MIMO, which is also known as Large-Scale AntennaSystems, Very Large MIMO, Hyper MIMO, Full-Dimension MIMO and ARGOS,makes use of a very large number of service antennas (e.g., hundreds orthousands) that are operated fully coherently and adaptively. Extraantennas may help by focusing the transmission and reception of signalenergy into smaller regions improving throughput and energy efficiency,in particularly when combined with simultaneous scheduling of a largenumber of user terminals (e.g., tens or hundreds). Massive MIMO wasoriginally envisioned for TDD operation, but can potentially be appliedalso in FDD operation. Massive MIMO may provide additional benefits,including the use of inexpensive low-power components, reduced latency,simplification of the MAC layer, and robustness to interference andintentional jamming.

Also shown in FIG. 2 is a UE 115 located in an overlapping area orregion between the UECM network zone and a nUECM network cell (e.g.,cell_3 having coverage area 110-d). The nUECM network cell may be a cellassociated with at least a portion of a wireless communications systemhaving a network-centric MAC layer. The UE 115 in the overlapping areamay receive one or more unified SYNC signals from base station 105-a incell_1 of zone_1 and/or from base station 105-b in cell_3. In otherwords, the UE 115 in the overlapping area may receive SYNC signals froma UECM network zone (e.g., cell_1 in zone_1) and/or from a nUECM networkcell (e.g., cell_3). For example, base station 105-a may generate andtransmit (e.g., broadcast), unified SYNC signals, which may identifyzone_1 and/or cell_1, as well as a nominal tone spacing being used byzone_1. Moreover, base station 105-b may transmit (e.g., broadcast)unified SYNC signals, which may identify cell_3.

After receiving the unified SYNC signals, whether from a UECM networkzone or a nUECM network cell, the UE 115 in the overlapping area mayprocess the unified SYNC signals to determine whether the networktransmitting the signals is a UECM network or a nUECM network. The UE115 may also detect, where the network is a UECM network, a nominalnumerology (e.g., tone spacing) being used by the network. The UE 115may detect the nominal numerology based on a number of copies of theunified SYNC signals received from a UECM network.

In some aspects, the unified SYNC signals may identify the zone, but maynot identify the cell from which the signal is transmitted. As such,base station 105-a in cell_1 may also transmit, via communicationmanagement component 340 (see e.g., FIG. 3), a cell-specific signal205-a where the cell-specific signal can indicate a cell identifier ofcell_1. Similarly, for example, base station 105-b in cell_3 may alsotransmit, via a cell-specific signal transmitting component 1340 (seee.g., FIG. 3), a cell-specific signal 205-b where the cell-specificsignal can indicate a cell identifier of cell_3. For example, thecell-specific signals may include MRSs that are scrambled using ascrambling code that is associated with the cell identifier. In anotherexample, the cell-specific signals may include cell-specific SYNCsignals that are generated using a sequence (e.g., a binary sequence,m-sequence, Zadoff-Chu sequence, etc.) that is associated with the cellidentifier. Accordingly, UE 115 can receive the cell-specific signal(s)205-a and/or 205-b from cell_1 and/or cell 3, and may identify one ormore of the cells based on the corresponding cell-specific signal(s). Inanother example, UE 115 may identify a serving cell as one of cell_1 orcell_3 based on a received cell-specific signal, and/or may determineone or more neighboring cell identifiers, as described herein.

Referring to FIG. 3, a system block diagram 300 is shown that includes aportion of a wireless communications system having multiple UEs 115 incommunication with a base station 105 via communication links 125, wherethe base station 105 is also connected to a network 130. In an example,the UEs 115 may be examples of the UEs described in the presentdisclosure that are configured to perform mobility mode selection andmanagement, and may receive and process one or more unified SYNCsignals. Moreover, the base station 105 may be an example of the basestations described in the present disclosure that are configured toperform mobility mode selection and management, and may generate andtransmit MRSs and manage neighbor lists for one or more UEs 115. In someaspects, the UE 115 may utilize one or more MRSs and neighbor listinformation in order to minimize the blind zone search performed by theUE 115 during inter-zone mobility or handover. In some aspects, duringintra-zone mobility, the base station 105 may operate or be configuredto perform mobility mode selection procedures for a UE 115 based on thecurrent RRC state of the UE 115 or based on a determination that the UE115 transitions from one RRC state to another RRC state (see, e.g., FIG.15).

In an aspect, the base station (e.g., the base station 105) in FIG. 3may include one or more processors 305 and/or memory 302 that mayoperate in combination with communication management component 340 toperform the functions, methodologies (e.g., method 1700 or method 2000),or methods presented in the present disclosure. In accordance with thepresent disclosure, the communication management component 340 mayinclude a neighbor list management component 342 that provide a neighborlist to the UE 115. In some examples, the neighbor list may includeinformation such as a list of neighbor zone IDs and zone measurementconfiguration for the UE 115. Additionally or alternatively, theneighbor list may include neighbor cell information such as neighborcell IDs and cell measurement configuration. The communicationmanagement component 340 may include an optional MRS transmissioncomponent 344 configured for scrambling and/or transmitting an MRS tothe UE 115 such that the UE 115 may compare the MRS from the servingzone and the MRS from the target zone to determine whether to transitionfrom the serving zone to a target zone. The communication managementcomponent 340 may include a signal measuring component 346 configuredfor measuring a signal received from the UE 115 to determine whether totransmit the MRS. In the situation of UL-based mobility mode, the signalmeasuring component 346 may measure the one or more reference signalsreceived from the UE 115 in order to perform UE search/measurements anddetermine whether the UE 115 is a candidate for transitioning to adifferent zone or cell based on the signal quality measurement derivedfrom the one or more received reference signals.

According to the present aspects, the communication management component340 may include a mobility mode component 348 to control or communicatewith the UE 115 for performing mobility mode management and selection asdescribed herein. For example, the mobility mode component 348 mayperform identifying information for mobility mode selection, identifyingan RRC state of the UE 115, and/or determining or selecting a UL-basedmobility or a DL-based mobility based on some identified information(e.g., the UE 115 is at a cell/zone edge, or the UE 115 is operating ata certain RRC state) at the network, or at the base station 105, orreceived from one or more UEs (e.g., the UE 115). In an aspect, themobility mode component 348 of the base station 105 may have capabilityof supporting both UL-based and DL-based mobility simultaneously oradaptively. For example, the mobility mode component 348 may support orperform both UL-based mobility and DL-based mobility at the same time.

The one or more processors 305 may include a modem 320 that uses one ormore modem processors. The various functions related to thecommunication management component 340, and/or its sub-components, maybe included in modem 320 and/or processor 305 and, in an aspect, may beexecuted by a single processor, while in other aspects, different onesof the functions may be executed by a combination of two or moredifferent processors. For example, in an aspect, the one or moreprocessors 305 may include any one or any combination of a modemprocessor, or a baseband processor, or a digital signal processor, or atransmit processor, or a transceiver processor associated withtransceiver 370, or a system-on-chip (SoC). In particular, the one ormore processors 305 may execute functions and components included in thecommunication management component 340.

In some examples, the communication management component 340 and each ofthe sub-components may comprise hardware, firmware, and/or software andmay be configured to execute code or perform instructions stored in amemory (e.g., a computer-readable storage medium, such as memory 302discussed below). Moreover, in an aspect, the base station 105 in FIG. 3may include a radio frequency (RF) front end 390 and transceiver 370 forreceiving and transmitting radio transmissions to, for example, UEs 115.The transceiver 370 may coordinate with the modem 320 to transmitmessages generated by the communication management component 340 (e.g.,neighbor list information, MRSs, cell-specific SYNC signals, determinedor selected mobility mode, PRACH, PKACH, PCICH, PDCCH, PDSCH, etc.) tothe UEs 115. RF front end 390 may be connected to one or more antennas373 and can include one or more switches 392, one or more amplifiers(e.g., power amplifiers (PAs) 394 and/or low-noise amplifiers (LNAs)391), and one or more filters 393 for transmitting and/or receiving RFsignals on downlink channels and/or uplink channels. In an aspect, thecomponents of the RF front end 390 may connect with transceiver 370. Thetransceiver 370 may be coupled with one or more of the modem 320 and theprocessor(s) 305.

The transceiver 370 may be configured to transmit (e.g., via transmitter(TX) radio 375) and receive (e.g., via receiver (RX) radio 380) wirelesssignals through antenna(s) 373 via the RF front end 390. In an aspect,the transceiver 370 may be tuned to operate at specified frequenciessuch that the base station 105 may communicate with, for example, UEs115. In an aspect, for example, the modem 320 may configure thetransceiver 370 to operate at a specified frequency and power levelbased on the configuration of the base station 105 and communicationprotocol used by the modem 320.

The base station 105 in FIG. 3 may further include a memory 302, such asfor storing data used herein and/or local versions of applications orcommunication management component 340 and/or one or more of itssub-components being executed by processor 305. Memory 302 may includeany type of computer-readable medium usable by a computer or processor305, such as random access memory (RAM), read only memory (ROM), tapes,magnetic discs, optical discs, volatile memory, non-volatile memory, andany combination thereof. In an aspect, for example, memory 302 may be acomputer-readable storage medium that stores one or morecomputer-executable codes defining communication management component340 and/or one or more of its sub-components. Additionally oralternatively, the base station 105 may include a bus 311 for couplingone or more of the RF front end 390, the transceiver 374, the memory302, or the processor 305, and to exchange signaling information betweeneach of the components and/or sub-components of the base station 105.

Referring to FIG. 4, a block diagram 400 is shown that includes aportion of a wireless communications system having multiple UEs 115 incommunication with a base station 105 via communication links 125, wherethe base station 105 may be connected to a network 130. The UEs 115 maybe examples of the UEs described in the present disclosure that areconfigured to receive and process signals received from the base station105. In an example, the UEs 115 may be examples of the UEs described inthe present disclosure that are configured to perform mobility modeselection and management, and may receive and process one or moreunified SYNC signals. In addition, the base station 105 may be anexample of the base stations described in the present disclosure thatare configured to generate and transmit cell-specific and/orzone-specific signals. Moreover, the base station 105 may be an exampleof the base stations described in the present disclosure that areconfigured to perform mobility mode selection and management. In someaspects, the UE 115 may utilize one or more MRSs and neighbor listinformation in order to minimize the blind zone search performed by theUE 115 during inter-zone mobility or handover. In some aspects, duringintra-zone mobility, the UE 115 may operate or be configured to performmobility mode selection procedures based on the current RRC state of theUE or based on a determination that the UE 115 transitions from one RRCstate to another RRC state (see, e.g., FIG. 15).

In an aspect, the UE 115 in FIG. 4 may include one or more processors405 and/or memory 402 that may operate in combination with mobilitymanagement component 440 to perform the functions, methodologies (e.g.,methods 1700, 1800, and/or 1900), or methods presented in the presentdisclosure. In accordance with the present disclosure, the mobilitymanagement component 440 may include a neighbor identification component442 for receiving and processing a neighbor list received from a servingzone/cell that identifies, from a list of available zones/cells, asubset of neighbor zones or cells associated with the UE 115. In anaspect, the mobility management component 440 may include asynchronization (SYNC) signal decoding component 444 for receiving anddecoding a SYNC signal from one or more target zones or cells anddetermining whether the target zone is included in the neighbor listbased on the SYNC signal. In some examples, the SYNC signal may includecell-specific ID and/or zone-specific ID that identifies the source ofthe SYNC signal.

The mobility management component 440 may include a mobility modecomponent 446 for determining, selecting, and/or transitioning betweenthe DL mobility mode and the UL mobility mode based on satisfaction ofone or more conditions (e.g., the signal quality falling below athreshold based on the measurements of the reference signal). In someexamples, the one or more conditions may be related to a speed of the UE115, a speed threshold of the UE 115, a radio condition of the UE 115,location information of the UE 115, or signal measurements of the UE115. In an aspect, the mobility management component 440 may include anRRC state component 448 for determining or identifying informationrelated to a current RRC state of the UE 115, or information orcondition(s) related to the UE 115 transitioning from the current RRCstate to another RRC state, as described herein (see, e.g., FIG. 15).

The one or more processors 405 may include a modem 420 that uses one ormore modem processors. The various functions related to the mobilitymanagement component 440, and/or its sub-components, may be included inmodem 420 and/or processor 405 and, in an aspect, may be executed by asingle processor, while in other aspects, different ones of thefunctions may be executed by a combination of two or more differentprocessors. For example, in an aspect, the one or more processors 405may include any one or any combination of a modem processor, or abaseband processor, or a digital signal processor, or a transmitprocessor, or a transceiver processor associated with transceiver 470,or a system-on-chip (SoC). In particular, the one or more processors 405may execute functions and components included in the mobility managementcomponent 440.

In some examples, the mobility management component 440 and each of thesub-components may comprise hardware, firmware, and/or software and maybe configured to execute code or perform instructions stored in a memory(e.g., a computer-readable storage medium, such as memory 402 discussedbelow). Moreover, in an aspect, the UE 115 in FIG. 4 may include an RFfront end 490 and transceiver 470 for receiving and transmitting radiotransmissions to, for example, base stations 105. The transceiver 470may coordinate with the modem 420 to receive cell-specific and/orzone-specific signals to be processed by the mobility managementcomponent 440. RF front end 490 may be connected to one or more antennas473 and can include one or more switches 492, one or more amplifiers(e.g., PAs 494 and/or LNAs 491), and one or more filters 493 fortransmitting and receiving RF signals on uplink channels and downlinkchannels. In an aspect, the components of the RF front end 490 mayconnect with transceiver 470. The transceiver 470 may connect to one ormore of modem 420 and processors 405.

The transceiver 470 may be configured to transmit (e.g., via transmitter(TX) radio 475) and receive (e.g., via receiver (RX) radio 480) wirelesssignals through antennas 473 via the RF front end 490. In an aspect, thetransceiver 470 may be tuned to operate at specified frequencies suchthat the UE 115 can communicate with, for example, base stations 105. Inan aspect, for example, the modem 420 can configure the transceiver 470to operate at a specified frequency and power level based on theconfiguration of the UE 115 and communication protocol used by the modem420.

The UE 115 in FIG. 4 may further include a memory 402, such as forstoring data used herein and/or local versions of applications or themobility management component 440 and/or one or more of itssub-components being executed by processor 405. Memory 402 may includeany type of computer-readable medium usable by a computer or processor405, such as RAM, ROM, tapes, magnetic discs, optical discs, volatilememory, non-volatile memory, and any combination thereof. In an aspect,for example, memory 402 may be a computer-readable storage medium thatstores one or more computer-executable codes defining mobilitymanagement component 440 and/or one or more of its sub-components. In anaspect, for example, memory 402 may be a non-transitorycomputer-readable storage medium. Additionally or alternatively, the UE115 may include a bus 411 for coupling one or more of the RF front end490, the transceiver 474, the memory 402, or the processor 405, and toexchange signaling information between each of the components and/orsub-components of the UE 115.

FIG. 5 illustrates a call flow 500 of a network initiates UL mobilitymode to DL mobility mode reconfiguration in accordance with variousaspects of the present disclosure. The call flow may include a UE (e.g.,the UE 115 in FIGS. 1-4) in communication with a first access node 504(or AN₁). The first access node 504 may further include a first TRP 508and a first access node controller 510. In some examples, the wirelesscommunications systems (e.g., the wireless communications system 100 inFIG. 1) may also include a second access node 506 (or AN₂) having asecond TRP 512 and a second access node controller 514 associated withthe second access node 506. In some examples, for the UE 115, thetransceiver 470, one or more of the processors 405, the memory 402, themodem 420, the mobility management component 440, and/or itssub-components may be configured to perform one or more aspects of thecall flow 500.

The UE 115, at block 1 in FIG. 5, may establish an RRC connection withthe first access node 504. In an aspect, a serving cluster may includethe first TRP 508. At block 2, the UE 115 may move into RRC_COMMONstate, e.g., with the first access node 504. In some aspects, the UE 115may operate in accordance with UL mobility mode at the initiate state.At block 3, the UE 115 may transmit a PUMICH to the first access node504. In some examples, the PUMICH may include the same UE-ID as theUE-ID used in the source zone, a new UE-ID which may be assigned by thetarget zone and sent over an interface by the source zone to the targetzone, or an initial access UE-ID which may be used when the UE 115accesses a zone for the first time. In some aspects, the initial accessUE-ID may be either randomly generated or signaled by system informationor hard-coded in a specification. The network may monitor the PUMICH andreference signals from the UE 115 to determine the signal qualitybetween the first access node 504 and the UE 115.

At block 4 in FIG. 5, the first TRP 508 may determine whether the PUMICHbecomes less than a threshold. When the first TRP 508 determines thatthe PUMICH has become less than a threshold at block 4, the first TRP508 may, at block 5, transmit a measurement report to the first accessnode controller 510. At block 6, the first access node controller 510may determine whether to switch the UE mobility mode from a UL mobilitymode to a DL mobility mode based on the measurement report indicatingthat the signal quality between the first access node 504 and the UE 115has fallen below a threshold. Accordingly, the first access nodecontroller 510 may generate an RRC connection reconfiguration messagefor transmission to the first TRP 508 at block 7. In an example, the RRCconnection reconfiguration message may include a UE mobility modeconfiguration (e.g., UE mobility mode configuration =DL measurementbased mobility). In an aspect, the RRC connection reconfigurationmessage may instruct the first TRP 508 (and the UE 115) to switch fromUL mobility mode to DL mobility mode. In some aspects, theinstruction(s) to switch is/are forwarded to the UE 115 by the first TRP508 in a PKACH at block 7 a (e.g., paging indicator=true). At block 7 b,the UE 115 may begin monitoring the PCICH (e.g., the UE 115 may monitorand receive a Physical Cell ID (PCI) over the PCICH). At block 7 c, theUE 115 may receive the RRC connection reconfiguration message (e.g.,mobility mode configuration) from the first TRP 508. In some examples,the RRC connection reconfiguration message in the illustrated examplemay also include a neighbor list for the UE 115. The neighbor list mayinclude one or more of: a neighbor zone list, neighbor cell list,neighbor RAT information, or neighbor frequency information associatedwith the UE 115. The UE 115 may utilize the neighbor list to reduce theprocessing requirements of blind zone search steps to execute by onlyconsidering SYNC signals from a subset of the target zones or cells.Accordingly, at block 7 d, the UE 115 may start a SYNC search and DLmeasurements, and may switch the operating or mobility mode from ULmobility mode to DL mobility mode. At block 7 e, the UE 115 may transmitan RRC connection confirmation message (e.g.,RRCConnectionReconfigurationComplete) to the first access node 504(e.g., the first access node controller 510) informing the network thatthe UE 115 has switched the operating or mobility mode from UL mobilitymode to DL mobility mode.

Thereafter, in an aspect at block 8 in FIG. 5, for example, the UE 115may receive a measurement reference signal (MRS) from a serving zone orcell (e.g., the first access node 504 or the first TRP 508). At block 9,the UE 115 may also receive a SYNC signal from the second access node506 (e.g., target zone or cell) or the second TRP 512. The SYNC signalmay include a cell-specific ID (e.g., a cell ID) and/or zone-specific ID(e.g. a zone ID) that identifies the source of the SYNC signal. In someexamples, the UE 115 may determine whether the target zone or cell(e.g., second access node 506) is included in the neighbor list. If thezone ID or cell ID of the second access node 506 matches the zone ID orcell ID identified in the neighbor list, the UE 115 may further decodethe MRS received from the target zone/cell at block 9 a. However, if thezone ID or cell ID of the second access node 506 does not match the zoneID or cell ID identified in the neighbor list, the UE 115 may ignore thesubsequent MRS from the second access node 506.

In an aspect, at block 10 in FIG. 5, the UE 115 may evaluate themeasured results (e.g., the measured results of one or more MRSs), andmay make a mobility decision. In some examples, if the zone ID or cellID of the SYNC signal (e.g., received at block 9) is included in theneighbor list, the UE 115 may compare the MRS(s) of the servingzone/cell and the MRS of the target zone/cell to determine whether totransition to the target zone or cell based on the comparison. In someaspects, in addition to the target zone or cell, the UE 115 maytransition from a serving RAT to a target RAT, or from a servingfrequency to a target frequency based on the MRS(s) of the first accessnode 504 and/or the second access node 506. In an aspect, the UE 115 mayevaluate different type of MRS(s) (e.g., cell-specific MRS (MRS-C) orzone-specific MRS (MRS-Z)) for mobility decision (e.g., based on thedetected SYNC type). For example, if the detected SYNC indicates anone-zone deployment (e.g., for deployment with asynchronous cells), theUE 115 may compare the serving TRP's MRS-C and the neighbor TRPs' MRS-C.If the detected SYNC indicates a zone deployment, the UE 115 may comparethe MRS-Zs of serving and neighbor zones. In some examples, the UE 115may evaluate the measured results, and may make a decision whether toswitch or transition the mobility mode (e.g., from UL mobility mode toDL mobility mode, or from DL mobility mode to UL mobility mode). In someimplementations, for example, UL-based mobility is deployed in a zone(e.g., with synchronous cells), and a none-zone deployment may useDL-based mobility only.

FIG. 6 illustrates a call flow 600 of a UE requested UL mobility mode toDL mobility mode switch reconfiguration in accordance with aspects ofthe present disclosure. The call flow 600 illustrates a UE (e.g., the UE115 in FIGS. 1-4) in communication with a first access node 604. Thefirst access node 604 may further include a first TRP 608 and a firstaccess node controller 610. In some examples, the wirelesscommunications systems (e.g., the wireless communications system 100 inFIG. 1) may also include a second access node 606 having a second TRP612 and a second access node controller 614 associated with the secondaccess node 606. In some examples, for the UE 115, the transceiver 470,one or more of the processors 405, the memory 402, the modem 420, themobility management component 440, and/or its sub-components may beconfigured to perform one or more aspects of the call flow 600.

Similar to FIG. 5, the UE 115 at block 1 in FIG. 6 may establish an RRCconnection with the first access node 604. In an aspect, a servingcluster may include the first TRP 608. At block 2, the UE 115 may moveinto RRC_COMMON state, e.g., with the first access node 604. In someaspects, the UE 115 may operate in accordance with UL mobility mode atthe initiate state. In the illustrated example, although the UE 115 isinitially operating in a UL mobility mode, the UE 115 may notnecessarily wait on the network to initiate the UE's transition from ULmobility mode to DL mobility mode when the signal quality between the UE115 and the first access node 604 falls below a threshold (e.g., incontrast to the call flow 500 shown in FIG. 5). Instead, as shown inblock 3 in FIG. 6, the UE 115, while in UL mobility mode, may stillreceive MRS(s) from the serving zone or cell (e.g., first access node604). At block 3 a, the UE 115 may determine whether signal quality isfalling below a threshold based on the received MRS. If the signalquality is less than a threshold, the UE 115, at block 4 in FIG. 6, mayrequest the network to initiate an RRC connection reconfiguration toallow the UE 115 to switch from UL mobility mode to DL mobility mode. Atblock 5, the UE 115 may send or transmit one or more UL signals, forexample, a UL signal measurement report, and/or a request for DLmeasurement configuration or reconfiguration. Once the first TRP 608receives the UL signal measurement report (e.g., with a request for DLmeasurement configuration or reconfiguration) from the UE 115, at block5 a, the first TRP 608 may send or forward a request for measurementconfiguration change or reconfiguration (e.g., a DL measurement basedrequest) to the first access node controller 610. In some aspects, block6 to block 9 of the call flow 600 in FIG. 6 may follow block 7 to block10 of the call flow 500 in FIG. 5. In other words, the network (e.g.,the first access node 604 and/or the second access node 606) mayinitiate one or more steps at block 6 to block 9 in FIG. 6 similar tothose identified in FIG. 5 (e.g., at block 7 to block 10 of the callflow 500).

FIG. 7 illustrates a call flow 700 for an autonomous switch from ULmobility mode to DL mobility mode in accordance with various aspects ofthe present disclosure. The call flow 700 illustrates a UE (e.g., the UE115) in communication with a first access node 704. The first accessnode 704 may further include a first TRP 708 and a first access nodecontroller 710. In some examples, the wireless communications systems(e.g., the wireless communications system 100 in FIG. 1) may alsoinclude a second access node 706 having a second TRP 712 and a secondaccess node controller 714 associated with the second access node 706.In some examples, for the UE 115, the transceiver 470, one or more ofthe processors 405, the memory 402, the modem 420, the mobilitymanagement component 440, and/or its sub-components may be configured toperform one or more aspects of the call flow 700.

Similar to FIG. 6, the UE 115 at block 1 in FIG. 7 may establish an RRCconnection with the first access node 704. In an aspect, a servingcluster may include the first TRP 708. At block 2, the UE 115 may moveinto RRC_COMMON state, e.g., with the first access node 704. In someaspects, the UE 115 may operate in accordance with UL mobility mode atthe initiate state. At block 3, the UE 115, while in UL mobility mode,may receive one or more MRSs from the serving zone or cell (e.g., firstaccess node 704). At block 3 a, the UE 115 may determine whether thesignal quality is falling below a threshold based on the received one ormore MRSs.

In the illustrated example, and in contrast to FIG. 6, the UE 115 maynot request the network for RRC connection (re)configuration to switchfrom UL mobility mode to DL mobility mode when the signal qualitybetween the first access node 704 and the UE 115 falls below a thresholdbased on the MRS from the first access node 704. Instead, as shown inblock 4 in FIG. 7, the UE 115 may start a SYNC search and/or perform DLmeasurement if certain criteria are met. In an example, afterdetermining that the signal quality is above a certain threshold, the UE115 may be still in the current mobility mode and/or with the currentserving zone. In another example, after determining that the signalquality has fallen below a certain threshold, the UE 115 mayunilaterally start SYNC search and DL measurement (e.g., by switching UEoperating or mobility mode from UL mobility mode to DL mobility mode)without waiting for RRC connection (re)configuration message from thenetwork. In such condition (e.g., the signal quality has fallen below acertain threshold), for example, the UE 115 may instead request thenetwork (e.g., serving zone or cell) to transmit the neighbor list tothe UE 115 such that the UE 115 may minimize the blind zone searchprocedures to a subset of zones, cells, RATs, or frequencies.

In some aspects, block 5 to block 7 of the call flow 700 in FIG. 7 mayfollow block 7 to block 9 of the call flow 600 in FIG. 6. In otherwords, the network (e.g., the first access node 704 and/or the secondaccess node 706) may initiate one or more steps at block 5 to block 7 inFIG. 7 similar to those identified in FIG. 6 (e.g., at block 7 to block9 of the call flow 600).

FIG. 8 illustrates a call flow 800 for a UE requested DL mobility modeto UL mobility mode reconfiguration in accordance with various aspectsof the present disclosure. The call flow 800 illustrates a UE (e.g., theUE 115) in communication with an access node 804. The access node 804may further include a TRP 806 and an access node controller 808. As withthe transition from UL mobility mode to DL mobility mode, call flow 800shows an example where the UE may request transition from DL mobilitymode to UL mobility mode from the network when one or more conditionsare satisfied. In some examples, for the UE 115, the transceiver 470,one or more of the processors 405, the memory 402, the modem 420, themobility management component 440, and/or its sub-components may beconfigured to perform one or more aspects of the call flow 800.

In FIG. 8, the UE 115 at block 1 may establish an RRC connection withthe access node 804. In an aspect, a serving cluster may include the TRP806. At block 2, the UE 115 may move into RRC_COMMON state, e.g., withthe access node 804. In some aspects, the UE 115 may operate inaccordance with DL mobility mode at the initiate state. At block 3, theUE 115, while in DL mobility mode, may receive one or more MRSs from theserving zone or cell (e.g., the access node 804).

At block 4 in FIG. 8, certain criteria may be met to trigger a mobilitymode switch. In an example, when the UE 115 (e.g., operating in DLmobility mode) determines that the UE mobility speed is above a certainthreshold, the UE 115 may request a mobility mode switch to a ULmobility mode which may be better suited for high mobility UEs. In someexamples, the UE speed may be estimated based on the Doppler effectmeasurements or number of cell selections during a specific time period.In some examples, the criteria to trigger a mobility mode switch mayinclude UE mobility speed being above a certain threshold, or DLreference signal quality, or a combination of thereof

At block 5, the UE 115 may send or transmit one or more UL signals, forexample, a request for a particular mobility mode (e.g., a ULmeasurement based mobility request) to the TRP 806. Once the TRP 806receives the one or more UL signals (e.g., with a request for ULmeasurement based mobility) from the UE 115, at block 6, the TRP 806 maysend a request for mobility mode switch (e.g., a request to switch to aUL-based mobility mode) to the access node controller 808. In an aspect,at block 6, the access node controller 808 may determine whether toswitch the UE mobility mode from a DL mobility mode to a UL mobilitymode based on the information provided at block 4 and/or block 5.

Accordingly, based on the request (e.g., the request sent from the UE115 and forwarded by the TRP 806) for transition to the UL mobilitymode, the access node 804 (e.g., by the access node controller 808) maymake a determination (e.g., whether to switch or transition the mobilitymode) at block 6, and may generate an RRC connection reconfigurationmessage for the TRP 806 and the UE 115 to initiate the mobility modeswitch. In an example, the access node controller 808 may generate anRRC connection reconfiguration message for transmission to the TRP 806at block 7. In an example, the RRC connection reconfiguration messagemay include a UE mobility mode configuration (e.g., UE mobility modeconfiguration=UL measurement based mobility or UL-based mobility). In anaspect, the RRC connection reconfiguration message may instruct the TRP806 (and the UE 115) to switch from DL mobility mode to UL mobilitymode. In some aspects, the instruction(s) to switch is/are forwarded tothe UE 115 by the TRP 806 in a message (e.g., a paging indication, or apaging message) at block 7 a. At block 7 b, the UE 115 may receive theRRC connection reconfiguration message (e.g., mobility modeconfiguration) from the TRP 806. In some examples, the RRC connectionreconfiguration message in the illustrated example may also include aneighbor list for the UE 115 as discussed herein. Accordingly, at block7 c, the UE 115 may switch the operating or mobility mode from DLmobility mode to UL mobility mode, and start UL measurement basedmobility operation(s). At block 7 d, the UE 115 may transmit an RRCconnection confirmation message (e.g., anRRCConnectionReconfigurationComplete message) to the access node 804(e.g., to the access node controller 808) informing the network that theUE 115 has switched the operating or mobility mode from DL mobility modeto UL mobility mode.

FIG. 9 illustrates a call flow 900 for an autonomous DL mobility mode toUL mobility mode switch in accordance with various aspects of thepresent disclosure. The call flow 900 illustrates a UE (e.g., the UE115) in communication with an access node 904. The access node 904 mayinclude a TRP 906 and an access node controller 908. In some examples,for the UE 115, the transceiver 470, one or more of the processors 405,the memory 402, the modem 420, the mobility management component 440,and/or its sub-components may be configured to perform one or moreaspects of the call flow 900.

In the illustrated example, the UE 115 may autonomously switch themobility modes (e.g., from DL mobility mode to UL mobility mode) withoutrequesting an RRC connection reconfiguration message from the accessnode when one or more conditions are satisfied. In some aspects, block 1to block 3 of the call flow 900 in FIG. 9 may follow block 1 to block 3of the call flow 800 in FIG. 8. At block 4 in FIG. 9, the UE 115 maydetermine whether certain criteria are met to trigger a mobility modeswitch. In some examples, the UE speed may be estimated based on theDoppler effect measurements or number of cell selections during aspecific time period. In some examples, the criteria to trigger amobility mode switch may include UE mobility speed being above a certainthreshold, or certain DL reference signal quality, or a combination ofthereof. In an aspect, the UE 115 may autonomously start the UL-basedmobility operation. In an example, when the UE 115 determines that theUE mobility speed exceeds a predetermined threshold, the UE 115 mayunilaterally switch its operating mode from DL mobility mode to ULmobility mode as the UL mobility mode may be better suited to handlehigh mobility UEs.

At block 5 in FIG. 9, the UE 115 may transmit a PUMICH to the accessnode 904 (e.g., the TRP 906). In some examples, the PUMICH may includethe same UE-ID as the UE-ID used in the source zone, a new UE-ID whichmay be assigned by the target zone and sent over an interface by thesource zone to the target zone, or an initial access UE-ID which may beused when the UE 115 accesses a zone for the first time. In someaspects, the initial access UE-ID may be either randomly generated orsignaled by system information or hard-coded in a specification. Thenetwork may monitor the PUMICH and reference signals from the UE 115 todetermine the signal quality between the access node 904 and the UE 115.At block 6, the TRP 906 may transmit a measurement report to the accessnode controller 908. In some examples, the measurement report mayinclude a UE-ID, and/or UMICH measurement results. Based on the receivedmeasurement report at block 6, the access node controller 908, at block7, may realize that the UE 115 which associated with the UE-ID (e.g.,the UE-ID received in the measurement report) has switched the mobilitymode from DL-based mobility to UL-based mobility, and accordingly, theaccess node controller 908 may start the UL-based mobility operationwith the UE 115.

FIG. 10 illustrates a call flow 1000 for a UL measurement basedintra-zone forward handover in accordance with various aspects of thepresent disclosure. The call flow 1000 illustrates a UE (e.g., the UE115) in communication with an access node 1004. The access node 1004 mayfurther include a plurality of TRPs (e.g., a first TRP 1006, one or moreTRPs 1008 (TRP₂ . . . TRP_(n)) and a node controller 1010. In someexamples, for the UE 115, the transceiver 470, one or more of theprocessors 405, the memory 402, the modem 420, the mobility managementcomponent 440, and/or its sub-components may be configured to performone or more aspects of the call flow 1000.

At block 1 in FIG. 10, the UE 115 may establish RRC connection with theaccess node 1004. In an aspect, a serving cluster may include the firstTRP 1006, and the UE 115 may be in a RRE DEDICATED state. At block 2,the UE 115 may monitor configurations for neighbor TRPs (e.g., theneighbor TRPs of the current serving TRP). At block 3, the UE 115 maytransmit a PUMICH to the first TRP 1006 (e.g., TRP₁) that may beforwarded to the plurality of neighbor TRPs. At block 4, when the UMICHat a second TRP 1008 (e.g., TRP₂) is greater than a threshold (e.g.,strong enough to serve the UE 115), the second TRP 1008 may transmit, atblock 5, a measurement report to the controller 1010 of the access node1004.

In some examples, the controller 1010, at block 6 in FIG. 10, may updatethe serving zone from the first TRP 1006 to the second TRP 1008 based onthe received measurement report. In such case, the first TRP 1006 maystill remain in the monitored set. At block 7, the controller 1010 mayprepare a handover command message and encrypt/integrity protect themessage with new keys identified by a next-hop chaining counter (NCC).In an aspect, an NCC is used to inform (or indicate) the UE 115 whethera new key should be derived via a vertical key derivation (e.g., an eNBkey (K_(eNB)) is derived from a core network (CN) key (e.g., K_(ASME)))or should be derived via a horizontal key derivation (e.g., a K_(eNB) isderived from the previously used K_(eNB)). In some examples, the UE 115may perform the vertical key derivation if the received NCC value isdifferent from the one stored in the UE 115, otherwise the UE 115performs the horizontal key derivation. In some aspects, the keysdiscussed herein may be one or more security keys used in Evolved PacketCore (EPC), Evolved Universal Terrestrial Access Network (E-UTRAN),and/or defined by 3GPP. For example, K_(eNB) is a key used in an AccessStratum (AS) (e.g., at the UE 115 and/or E-UTRAN) to derive an integrityprotection key and encryption keys for C-plane and/or U-plane, andK_(ASME) is used in CN to derive the K_(eNB) for the AS.

At block 7 a, the controller 1010 may transmit a serving TRP requestmessage to, for example, the second TRP 1008, that includes the handovercommand message. In some examples, the serving TRP request message mayinclude information related to the TRP destination, UE identity, a RRCstate (e.g., RRC_DEDICATED, and/or a handover (HO) command message. Inresponse, at block 7 b, the second TRP 1008 may allocate the radioresource according to the serving TRP request. The allocated radioresource identification information (e.g., Keep-Alive (KA) information,handover (HO) indication) may be transmitted to the UE 115 thereafter atblock 8. In some examples, the UE 115, block 8, begins monitoring thePCICH channel upon reception of the KA information and/or the HOindication. In some examples, KA information may be some informationwith one or more bits which carries ACK for PUMICH or a pagingindication. For example, the paging indication may indicates that thereis (or will be) one or more paging messages for the UE 115. In animplementation, the KA information may be carried in a PKACH.

At block 9 a in FIG. 10, the UE 115 may decipher and integrity verifythe handover command received from the second TRP 1008 based on anupdated keys identified by the NCC associated with the PCI. At block 9b, the UE 115 may reconfigure the lower layers according to the RRCmessage, and at block 9 c, the UE 115 may transmit a handover completemessage (e.g., HO Complete) to the second TRP 1008, and the handovercomplete message may be forwarded to the controller 1010. At block 10,the controller 1010 may switch paths for the UE 115 from the first TRP1006 (e.g., TRP₁) to the second TRP 1008 (e.g., TRP₂) upon receivinghandover complete message. At block 11, the controller 1010 may send aserving TRP release request message (e.g., with a UE identity or aUE-ID) to the first TRP 1006. Upon reception of the serving TRP releaserequest, at block 11 a, the first TRP 1006 may release all radioresources for the UE 115 (e.g., based on the received UE identity orUE-ID). At block 11 b, the first TRP 1006 may send a serving TRP releaseresponse message to the controller 1010. Accordingly, at block 12, themonitored set may be replaced with the neighbor TRPs of the currentserving TRP.

FIG. 11 illustrates a call flow 1100 for a UL measurement basedinter-zone backward handover in accordance with various aspects of thepresent disclosure. The call flow 1100 illustrates a UE (e.g., the UE115) in communication with a first access node 1104. The first accessnode 1104 may further include a first TRP 1108 and a first access nodecontroller 1110. In some examples, the wireless communications systems(e.g., the wireless communications system 100 in FIG. 1) may alsoinclude a second access node 1106 having a plurality of TRPs 1112 (e.g.,TRP₂, . . . TRP_(x), etc.) and a second access node controller 1114associated with the second access node 1106. In some examples, for theUE 115, the transceiver 470, one or more of the processors 405, thememory 402, the modem 420, the mobility management component 440, and/orits sub-components may be configured to perform one or more aspects ofthe call flow 1100.

In contrast to FIG. 10 that illustrates an intra-zone handover, callflow 1100 shows the steps for initiating a TRP change towards the targetzone from a first access node 1104 to the second access node 1106 basedon uplink measurements. At block 1 in FIG. 11, the UE 115 may establishRRC connection with the first access node 1104. In an aspect, a servingcluster may include the first TRP 1108. At block 2, the UE 115 maymonitor configurations for neighbor TRPs (e.g., the neighbor TRPs of thecurrent serving TRP). At block 3, the UE 115 may transmit one or moreuplink reference signals to the first TRP 1108 (e.g., TRP₁) that may beforwarded to the plurality of neighbor TRPs (with the second access node1106). At block 4, for example, when the UMICH at the second TRP 1112(e.g., TRP₂) is greater than a threshold (e.g., strong enough to servethe UE 115), the second TRP 1112 may transmit, at block 5, a measurementreport to the second access node controller 1114 of the second accessnode 1106. On the other hand, at block 5′, the first TRP 1108 of thefirst access node 1104 may prepare a measurement report of the signalquality based on the one or more uplink reference signals transmitted bythe UE 115 (e.g., UL reference signal measurement results at the firstTRP 1108).

At block 6 in FIG. 11, the second access node controller 1114 may send aUE mobility notification to the first access node controller 1110, basedon the received measurement report at block 5. In some examples, the UEmobility notification may include the UE-ID, or UMICH measurementresults at the second access node 1106. At block 6 a, after reception ofthe UE mobility notification, the first access node controller 1110 maydetermine a serving TRP change/switch towards the target zone (e.g., thesecond TRP 1112). In some examples, the determination at block 6 a mayinclude determining whether the UMICH at the second TRP 1112 (that isassociated with the second access node 1106) exceeds the UMICH at thefirst TRP 1108 associated with the first access node 1104. At block 7,if the UMICH at the second TRP 1112 exceeds the UMICH at the first TRP1108, the first access node controller 1110 may transmit a handoverrequest to the second access node controller 1114 (e.g., to switch pathsfor the UE 115 from the first access node 1104 to the second access node1106).

At block 8 in FIG. 11, the second access node controller 1114 may send aserving TRP request to the second TRP 1112. In some examples, theserving TRP request may include the target TRP (e.g., the second TRP1112), the UE identity (e.g., the UE-ID), and/or a handover (HO) commandmessage. At block 8 a, the second access node controller 1114 mayreceive a confirmation via a serving TRP response message from thesecond TRP 1112. At block 9, the second access node controller 1114 maysend a handover request acknowledge (e.g., with an HO command) to thefirst access node controller 1110. Upon reception of the handoverrequest acknowledge, at block 9 a, the first access node controller 1110may send an RRC connection reconfiguration message (e.g., the HOcommand) to the first TRP 1108.

At block 9 b in FIG. 11, the KA information and/or the paging indicationmay be transmitted to the UE 115 from the first TRP 1108. In someexamples, at block 9 c, the UE 115 begins monitoring and receiving thePCICH channel upon reception of the KA information and/or the pagingindication. At block 9 d, the RRC connection reconfiguration message(e.g., the HO command) may be transmitted from the first TRP 1108 to theUE 115. Accordingly, at block 9 e, the UE 115 may perform one or more HOprocedures for switching to the second TRP 1112. At block 9 f, the UE115 and the second TRP 1112 may start to perform one or more randomaccess operations. At block 9 g, the UE 115 may transmit an RRCconnection confirmation message (e.g., anRRCConnectionReconfigurationComplete message) to the second access nodecontroller 1114. At block 10, one or more paths may be switched, for theUE 115, from the first access node 1104 to the second access node 1106upon receiving the RRC connection confirmation message. In an aspect, atblock 10, the first access node 1104 may release all radio resources forthe UE 115 (e.g., UE context).

FIG. 12 illustrates a call flow 1200 for a DL measurement basedinter-zone mobility for backward handover in accordance with variousaspects of the present disclosure. The call flow 1200 illustrates a UE(e.g., the UE 115) in communication with a first access node 1204. Thefirst access node 1204 may further include a first TRP 1208 and a firstaccess node controller 1210. In some examples, the wirelesscommunications systems (e.g., the wireless communications system 100 inFIG. 1) may also include a second access node 1206 having a plurality ofTRPs 1212 (e.g., TRP₂, . . . TRP_(x), etc.) and a second access nodecontroller 1214 associated with the second access node 1206. In someexamples, for the UE 115, the transceiver 470, one or more of theprocessors 405, the memory 402, the modem 420, the mobility managementcomponent 440, and/or its sub-components may be configured to performone or more aspects of the call flow 1200.

In contrast to FIG. 11 that initiates the handover to the second accessnode 1106 based on measurements from UL mobility mode, call flow 1200illustrates a method where the UE 115 starts PUMICH transmission towardsa target zone upon determining to move from the first access node 1204to the second access node 1206 based in part on the DL measurement. Inan aspect, at block 1 in FIG. 12, the UE 115 may start DL measurementsand DL-based mobility mode operation(s). At block 2, the UE 115 maydetermine to move to another zone (e.g., a target zone) based on the DLmeasurements. At block 3, the UE 115 starts PUMICH transmissions towardsa target zone. In an example, at block 3 a, the UE 115 may transmitPUMICH to the target zone, e.g., the second TRP 1212. In some aspects,block 4 to block 10 of the call flow 1200 in FIG. 12 may follow block 4to block 10 of the call flow 1100 in FIG. 11.

FIG. 13 illustrates a call flow 1300 for a DL measurement basedinter-zone mobility in accordance with various aspects of the presentdisclosure. The call flow 1300 illustrates a UE (e.g., the UE 115) incommunication with a first access node 1304. The first access node 1304may further include a first TRP 1308 and a first access node controller1310. In some examples, the wireless communications systems (e.g., thewireless communications system 100 in FIG. 1) may also include a secondaccess node 1306 having a plurality of TRPs 1312 (e.g., TRP₂, . . .TRP_(x), etc.) and a second access node controller 1314 associated withthe second access node 1306. In some examples, for the UE 115, thetransceiver 470, one or more of the processors 405, the memory 402, themodem 420, the mobility management component 440, and/or itssub-components may be configured to perform one or more aspects of thecall flow 1300.

In contrast to FIG. 12 that illustrated a backward handover forinter-zone mobility, FIG. 13 illustrates an example of a forwardhandover based on DL measurements in inter-zone mobility. A differencebetween the downlink based backward and forward handover is that forbackward handover (e.g., in FIG. 12), the UE 115 may monitor the sourcezone's PHY channels. In contrast, for the forward handover (e.g., inFIG. 13), the UE 115 may monitor the target zone's PHY channels toreceive the handover command from the RAN.

In some aspects, block 1 to block 9 of the call flow 1300 in FIG. 13 mayfollow block 1 to block 9 of the call flow 1200 in FIG. 12. At block 10in FIG. 13, the second access node controller 1314 may send an RRCconnection re-establishment message (e.g., a radio resourceconfiguration) to the second TRP 1312. Upon reception of the RRCconnection re-establishment message, at block 10 a, the KA informationand/or the HO indication may be transmitted to the UE 115 from thesecond TRP 1312. In some examples, at block 10 b, the UE 115 beginsmonitoring and receiving the PCICH channel upon reception of the KAinformation and/or the HO indication from the second TRP 1312. At block10 c, the RRC connection re-establishment message (e.g., the radioresource configuration) may be transmitted or forwarded from the secondTRP 1312 to the UE 115. Accordingly, at block 10 d, the UE 115 mayperform one or more HO procedures for switching to the second TRP 1312.At block 10 e, the UE 115 and the second TRP 1312 may start to performone or more random access operations. At block 10 f, the UE 115 maytransmit an RRC connection confirmation message (e.g., anRRCConnectionReconfigurationComplete message) to the second access nodecontroller 1314. At block 11, one or more paths may be switched, for theUE 115, from the first access node 1304 to the second access node 1306upon receiving the RRC connection confirmation message. In an aspect, atblock 11, the first access node 1304 may release all radio resources forthe UE 115 (e.g., UE context).

FIG. 14 illustrates an example structure of synchronization (SYNC)channels. In some examples, a cell may transmit two separate SYNCsignals to the UE: a cell-specific SYNC signal and/or a zone-specificSYNC signal. In an aspect, a cell-specific SYNC channel/signal 1400 mayinclude a PSS-C 1402, a SSS-C 1404, a PBCH-C 1406, and/or an MRS-C 1408.As noted, the cell may also provide a zone-specific SYNC channel/signal1420 to the UE 115 that may include a PSS-Z 1422, a SSS-Z 1424, a PBCH-Z1426, and/or an MRS-Z 1428 associated with the target zone. In someexamples, the cell-specific SYNC signal 1400 and zone-specific SYNCsignal 1420 may be decoupled such that flexible SYNC switching may beachieved for supporting different mobility modes.

In an aspect, the UE 115 may use the zone-specific information to decodethe zone-specific MRS (e.g., MRS-Z 1428). In some examples, the UE 115may perform zone monitoring based on the zone-specific MRS (e.g., MRS-Z1428). Further, the MRS may be used to determine an initial outer looppower control (OLPC) setting for UMICH transmission. In an example, theUE 115 may periodically send an uplink measurement indication signal onthe uplink UMICH, and the network may change the serving cell based onreception of the UMICH. If the zone-specific MRS signal strength becomesless than a threshold, the UE 115 may perform inter-zone mobility (e.g.,based on a neighbor zone identified by the network) or perform anemergency cell search according to a downlink mobility procedure.

In some examples, the zone-specific information may be self-discoverableby the UE 115. For example, the cell may transmit a cell-specific SYNCsignal (e.g., the cell-specific SYNC signal 1400) including the PSS-C1402, the SSS-C 1404, and the PBCH-C 1406 as well as a zone-specificSYNC signal (e.g., the zone-specific SYNC signal 1420) including thePSS-Z 1422, the SSS-Z 1424 and the PBCH-Z 1426. In this example, the UE115 may perform a zone search by detecting the zone-specific SYNC signal(e.g., the zone-specific SYNC signal 1420). For example, a zone searchprocedure may be similar to a cell search procedure, except using the PSS-Z 1422 and the SSS-Z 1424 to detect the zone ID and timing and/orfrequency. In an aspect, the UE 115 may then decode the PBCH-Z 1426,which may provide information for transmitting the UL UMICH. Afteracquiring the zone, the UE 115 may monitor the MRS-Z 1428. If the signalstrength of the MRS-Z 1428 is less than a threshold, the UE 115 mayperform inter-zone mobility (e.g., by acquiring a new zone) orperforming an emergency cell search according to a downlink mobilityprocedure. If the signal strength of the MRS-Z 1428 is greater than orequal to the threshold, the UE 115 may send or transmit the UL UMICH. Insome aspects, the zone-specific SYNC channel/signal may be turned ONwhen supporting or performing UL-based mobility.

In some aspects, the cell-specific SYNC signal 1400 and zone-specificSYNC signal 1420 may each be sent in the same subframe or in differentsubframes (e.g., same or different downlink centric subframes). In thecase that the cell-specific SYNC signal 1400 and the zone-specific SYNCsignal 1420 are transmitted on the same subframe, the cell-specific SYNCsignal 1400 and the zone-specific SYNC signal 1420 may be processedusing FDM or TDM. Additionally or alternatively, the cell-specific SYNCsignal 1400 and the zone-specific SYNC signal 1420 may each have same ordifferent periodicity.

In some aspects, a relative offset between the cell-specific SYNC signal1400 and the zone-specific SYNC signal 1420 may be signed in systeminformation. For example, after the UE 115 detects one SYNC signal type(e.g., cell-specific SYNC signal or zone-specific SYNC signal), the UEcan obtain the locations of the other SYNC signal type based on therelative offset that is signaled by the cell in the system information.In some examples, the cell ID and zone ID associated with thecell-specific SYNC signal 1400 and the zone-specific SYNC signal 1420,respectively, may be subdivided in a transmission bit stream. Forexample, the first portion may be allocated to the zone ID and thesecond portion allocated to the cell ID.

Referring to FIG. 15, an example radio resource control (RRC) statesdiagram 1500 is used for identifying a current RRC state, and/or an RRCstate transition of a UE (e.g., the UE 115 in FIG. 1). In some aspects,the UE may operate in an RRC state, or may transition from one RRC stateto another RRC state. These RRC states may be included in two modes, aConnected Mode and an Idle Mode. In FIG. 15, a Connected Mode mayinclude, but not limited to, an RRC-DEDICATED state 1502 and/or anRRC-COMMON state 1504. In an aspect, when the UE is in the RRC-DEDICATEDstate 1502, UE context may be included in a radio access network (RAN),and the UE may have available air interface resources assigned, and maytransmit and receive any data. In another aspect, when the UE is in theRRC-COMMON state 1504, similarly, there may be UE context in the RAN,but no assigned air interface resources for the UE, and the UE may onlytransmit and receive small data.

Still in FIG. 15, an Idle Mode may include, but not limited to, aREACHABLE-IDLE state 1506 (or an RRC-IDLE state) and/or a power savingmode 1508. In an aspect, when the UE is in the REACHABLE-IDLE state 1506(or the RRC-IDLE state), there may be no UE context in the RAN, noassigned air interface resources for the UE, and the UE may onlytransmit and receive small data. In another aspect, when the UE is inthe power saving mode 1508, there may be no UE context in the RAN, noassigned air interface resources for the UE, and the UE has no datatransmissions or receptions.

Referring to FIG. 16A, an example call flow 1600 shows signal exchangesbetween a UE (e.g., the UE 115 in FIG. 1) and an access node (AN) 1604for mobility mode selection and management when the UE 115 is in an RRCstate (e.g., the RRC-COMMON state 1504 in FIG. 15). In an aspect, thecall flow 1600 may be related to a UE-driven mobility mode switching,which may include switching from a UL mobility mode to a DL mobilitymode, and/or switching from a DL mobility mode to a UL mobility mode. Inparticular, the UE 115 sends a mobility mode request signal or message(e.g., via a physical layer procedure). In some examples, the mobilitymode request signal or message may include random access channel (RACH)information, UE identification (e.g., UE-ID), and/or mobility modeinformation in one bit or multiple bits (e.g., mobility mode switchingindication, a target or preferred mobility mode, or both). In animplementation, the one-bit mobility mode information may include a bit“0” for DL mobility mode or a bit “1” for UL mobility mode. In anotherimplementation, the one-bit mobility mode information may include a bit“1” for DL mobility mode or a bit “0” for UL mobility mode. In anexample, the one-bit mobility mode information (e.g., for mobility modeswitching request) may include one bit for switching from a DL mobilitymode to a UL mobility mode, or one bit for switching from a UL mobilitymode to an DL mobility mode.

In an aspect, the AN 1604 may then send a PKACH to acknowledge receivingthe request signal/message. The AN 1604 may also send a mobility modeindicator (with or without the PKACH) in response to the requestsignal/message. In an example, the mobility mode indicator may compriseone-bit information (e.g., “0” or “1”) indicating whether the networkaccepts (e.g., YES or NO) the mobility mode switching request sent fromUE 115 (e.g., in response to the one-bit mobility mode information sentfrom UE 115). In some examples, there is no paging indicator embedded inthe PKACH. In some examples, the UE 115 may optionally send a signal tothe network or AN 1604 (e.g., via a physical layer procedure) to informthe request completion.

Referring to FIG. 16B, another example call flow 1620 shows signalexchanges between the UE 115 and the AN 1604 for mobility mode selectionand management when the UE 115 is in an RRC state (e.g., the RRC-COMMONstate 1504 in FIG. 15). In an aspect, the call flow 1620 may be relatedto a UE-driven mobility mode switching, which may include switching froma UL mobility mode to a DL mobility mode. In particular, the UE 115sends a mobility mode request signal or message (e.g., via a physicallayer procedure). In some examples, the mobility mode request signal ormessage may include RACH information, UE identification (e.g., UE-ID),and/or mobility mode information in one bit or multiple bits (e.g.,mobility mode switching indication, a target or preferred mobility mode,or both). In an example, the one-bit mobility mode information mayinclude a bit “0” for DL mobility mode or a bit “1” for UL mobilitymode. In another example, the one-bit mobility mode information mayinclude a bit “1” for DL mobility mode or a bit “0” for UL mobilitymode. In an example, the one-bit mobility mode information (e.g., formobility mode switching request) may include one bit for switching froma DL mobility mode to a UL mobility mode, or one bit for switching froma UL mobility mode to an DL mobility mode.

In an aspect, the network or the AN 1604 may send a PKACH to acknowledgereceiving the request signal/message. The network or the AN 1604 mayalso send a mobility mode indicator in response to the requestsignal/message. In an example, the mobility mode indicator may compriseone-bit information (e.g., “0” or “1”) indicating whether the networkaccepts (e.g., YES or NO) the mobility mode switching request sent fromthe UE 115 (e.g., in response to the one-bit mobility mode informationsent from the UE 115). In some examples, the UE 115 may be aware of oneor more zones (with a plurality of cells) in the network, but not beaware of a certain cell or cells for communications. In this case, thenetwork or the AN 1604 may optionally send a Physical Cell ID Channel(PCICH) to the UE 115 to inform or indicate one or more cellidentifications (e.g., Cell ID(s)), and the UE 115 may use the informedor indicated one or more cell identifications for mobility modeswitching, for example, from a UL mobility mode to a DL mobility mode.In some examples, the network or the AN 1604 may send a mobility modeconfiguration response via a Physical Downlink Control Channel (PDCCH)or a Physical Downlink Shared Channel (PDSCH). UE 115 may then decodethe PDCCH/PDSCH using, for example, a Mobility Indication-Radio NetworkTemporary Identifier (MI-RNTI), and therefore, the UE 115 may not benecessary to go into or switch to an RRC-DEDICATED state (e.g., in FIG.15) to decode the received PDCCH/PDSCH.

For purposes of simplicity of explanation, the methods discussed hereinare shown and described as a series of acts, it is to be understood andappreciated that the method (and further methods related thereto) is/arenot limited by the order of acts, as some acts may, in accordance withone or more aspects, occur in different orders and/or concurrently withother acts from that shown and described herein. For example, it is tobe appreciated that a method could alternatively be represented as aseries of interrelated states or events, such as in a state diagram.Moreover, not all illustrated acts may be required to implement a methodin accordance with one or more features described herein.

FIG. 17 is a flowchart of an example method 1700 of mobility modeselection and management for wireless communications, in accordance withone or more aspects of the present disclosure. In an operational aspect,a UE such as UE 115 (FIG. 1), and/or a network entity such as basestation 105 (FIG. 1) may perform one or more aspects of the method 1700for mobility mode selection and management. For example, for basestation 105, one or more of the processors 305, the memory 302, themodem 320, the communication management component 340, and/or itssub-components (e.g., the signal measuring component 346, the mobilitymode component 348) may be configured to perform one or more aspects ofthe method 1700. In another example, for UE 115, one or more of theprocessors 405, the memory 402, the modem 420, the mobility managementcomponent 440, and/or its sub-components (e.g., the mobility modecomponent 446, the RRC state component 448) may be configured to performone or more aspects of the method 1700.

In an aspect, at block 1702, the method 1700 may include determiningthat a UE is operating in a first mobility mode. In an aspect, forexample, the mobility mode component 348/446 may identify or determinewhether the UE (e.g., the UE 115) is operating in a UL mobility mode ora DL mobility mode, as described herein.

In an aspect, at block 1704, the method 1700 may include determiningwhether the UE satisfies at least one condition associated with mobilityof the UE for mobility mode selection. In an aspect, for example, thecommunication management component 340, and/or its sub-components of thebase station 105 (e.g., the signal measuring component 346, the mobilitymode component 348), or the mobility management component 440, and/orits sub-components of the UE 115 (e.g., the mobility mode component 446,the RRC state component 448) may be configured to identify or determinewhether the UE satisfies at least one condition associated with mobilityof the UE for mobility mode selection. In some examples, the at leastone condition may include the signal quality falling below a thresholdbased on measurements of a reference signal. In some examples, the atleast one condition may be related to a speed of the UE 115, a speedthreshold of the UE 115, a radio condition of the UE 115, locationinformation of the UE 115, or signal measurements of the UE 115. In somefurther examples, the at least one condition may be related to a currentRRC state of the UE 115, or information or condition(s) related to theUE 115 transitioning from the current RRC state to another RRC state, asdescribed herein (see, e.g., FIG. 15).

In an aspect, at block 1706, the method 1700 may include selecting asecond mobility mode based on a determination that the UE satisfies theat least one condition, wherein each of the first mobility mode and thesecond mobility mode is a UL mobility mode or a DL mobility mode. In anaspect, for example, the communication management component 340, and/orits sub-components of the base station 105 (e.g., the mobility modecomponent 348), or the mobility management component 440, and/or itssub-components of the UE 115 (e.g., the mobility mode component 446) maybe configured to select or switch the mobility mode (e.g., a UL mobilitymode or a DL mobility mode) based on the determination(s) at block 1702and/or block 1704. For example, the mobility mode component 348 or themobility mode component 446 may be configured to transition the UE 115from the current mobility mode to the selected mobility mode, and theselected mobility mode may be the same or different from the currentmobility mode.

In another aspect of the method 1700, determining whether the UEsatisfies the at least one condition associated with mobility of the UEmay include determining at least one parameter associated with the UE,and the at least one parameter may include one or more of a speed of theUE, a speed threshold of the UE, a radio condition of the UE, locationinformation of the UE, or signal measurements of the UE.

In another aspect, the method 1700 may include determining that the atleast one parameter associated with the UE exceeds a threshold, andtransitioning the UE from the first mobility mode to the selected secondmobility mode based on the determination. In an example, the firstmobility mode may be a UL mobility mode and the second mobility mode maybe a DL mobility mode.

In another aspect, the method 1700 may include determining that the atleast one parameter associated with the UE is less than a threshold, andtransitioning the UE from the first mobility mode to the selected secondmobility mode based on the determination. In an example, the firstmobility mode may be a DL mobility mode and the second mobility mode maybe a UL mobility mode.

In another aspect, the method 1700 may include receiving the at leastone parameter in Minimum System Information Blocks (MSIB), wherein theat least one parameter is related to the mobility mode selection.

In another aspect, the method 1700 may include receiving a neighbor listfrom a serving zone, wherein the neighbor list includes informationassociated with at least one of a neighbor zone, a neighbor cell, aneighbor radio access technology (RAT), or a neighbor frequency.

In another aspect, the method 1700 may include receiving, at the UE, aneighbor list from a serving zone that identifies, from a list ofavailable zones, a subset of neighbor zones associated with the UE;receiving a synchronization (SYNC) signal from a target zone;determining whether the target zone is included in the neighbor listbased on the SYNC signal; comparing a reference signal of the servingzone to a reference signal of the target zone in response to adetermination that the target zone is included in the neighbor list; anddetermining whether to transition to the target zone based on thecomparison.

In another aspect of the method 1700, the determination of whether theUE satisfies the at least one condition associated with mobility of theUE may include the following: determining a current radio resourcecontrol (RRC) state of the UE, wherein the current RRC state is one ofan RRC-IDLE state, an RRC-COMMON state, or an RRC-DEDICATED state; ordetermining whether the UE transitions from a first RRC state to asecond RRC state, wherein each of the first RRC state and the second RRCstate is one of an RRC-IDLE state, an RRC-COMMON state, or anRRC-DEDICATED state.

In another aspect, the method 1700 may include determining that the UEtransitions from the first RRC state to the second RRC state, andselecting the mobility mode used in the first RRC state as the secondmobility mode.

In another aspect, the method 1700 may include determining that the UEtransitions from the first RRC state to the second RRC state; sending afirst message including a mobility mode recommendation; and receiving asecond message including a mobility mode configuration in response tothe first message.

In another aspect, the method 1700 may include handshaking with anetwork entity to select at least one of the UL mobility mode or the DLmobility mode via at least one of a physical layer procedure, a mediaaccess control (MAC) layer procedure, or dedicated RRC messages.

In another aspect, the method 1700 may include determining that the UEtransitions from the first RRC state to the second RRC state; receivingan RRC reconfiguration message; and selecting the second mobility modebased on the received RRC reconfiguration message.

In another aspect, the method 1700 may include determining that the UEtransitions from the first RRC state to the second RRC; and initiating amobility mode switching by sending an RRC connection setup requestmessage or receiving a paging message.

In another aspect, the method 1700 may include receiving, at the UE, apaging message; and selecting at least one of the UL mobility mode orthe DL mobility mode based on the determination of the current RRC stateand the received paging message.

In another aspect, the method 1700 may include sending, by the UE, amobility mode request message in response to a determination that the UEsatisfies at least one condition; and receiving a Physical Keep-AliveChannel (PKACH) including at least an acknowledgement or a mobility modeindicator in response to the mobility mode request message.

In another aspect, the method 1700 may include sending, by the UE, amobility mode request message in response to a determination that the UEsatisfies at least one condition; receiving a downlink signal includinga mobility mode configuration response message in response to themobility mode request message; and decoding the downlink signal using amobility indication.

In another aspect, the method 1700 may include receiving asynchronization (SYNC) signal from a cell, wherein the SYNC signalincludes a cell-specific SYNC and a zone-specific SYNC, and determiningwhether to decode a measurement reference signal (MRS) from the cellbased on a cell identification (ID) or a zone ID associated with theSYNC signal.

In another aspect of the method 1700, the determination of whether todecode the MRS from the cell may include determining whether the cell IDor the zone ID is included in the neighbor list.

In another aspect, the method 1700 may include transmitting a physicaluplink measurement indication channel (PUMICH) to a target zone, whereinthe PUMICH includes UE identification (ID) as the UE-ID used in a sourcezone, a new UE-ID which is assigned by the target zone, or an initialaccess UE-ID.

In another aspect of the method 1700, comparing the reference signal ofthe serving zone to the reference signal of the target zone may includethe following: measuring a first signal quality based on the referencesignal of the serving zone; measuring a second signal quality based onthe reference signal of the target zone; and determining a signalquality difference between the first signal quality and the secondsignal quality.

In another aspect, the method 1700 may include determining whether amobility trigger condition is satisfied, wherein the mobility triggercondition includes a first signal quality associated with the servingzone falls below a threshold; and wherein receiving the neighbor listfrom the serving zone is in response to the mobility trigger conditionbeing satisfied.

In another aspect of the method 1700, the neighbor list may include oneor both of a neighboring zones or neighboring cells associated with theUE.

In another aspect, the method 1700 may include determining that thetarget zone is not included in the neighbor list based on the SYNCsignal or that the neighbor list does not include neighboring zones;determining to transition to a suitable target cell included in theneighbor list; and transitioning the UE from the serving zone to thetarget cell.

In another aspect of the method 1700, the SYNC signal may include anindication of one or both of a cell ID or a zone ID.

In another aspect of the method 1700, the determination of whether thetarget zone is included in the neighbor list based on the SYNC signalmay include determining whether the zone ID is included in the neighborlist.

In an aspect of the method 1700, a neighbor list may be received fromthe serving zone either periodically or based on an event trigger. Inanother aspect of the method 1700, the neighbor list may be received inresponse to a request initiated by the UE to the serving zone totransmit the neighbor list. In another aspect of the method 1700, theneighbor list may be received without the UE requesting the serving zoneto transmit the neighbor list.

FIG. 18 illustrates a flowchart of an example method 1800 of mobilitymode management for inter-zone mobility for wireless communications, inaccordance with aspects of the present disclosure. In an aspect, themethod 1800 may be performed by a UE (e.g., the UE 115). Although themethod 1800 is described below with respect to the elements of the UE115, other components may be used to implement one or more of the stepsdescribed herein.

At block 1802, the method 1800 may include receiving, at the UE, aneighbor list from a serving zone that identifies, from a list ofavailable zones, a subset of neighbor zones associated with the UE. Insome aspects, the neighbor list may be received from the serving zone inresponse to the mobility trigger condition being satisfied. For example,the UE 115 may determine whether a mobility trigger condition issatisfied (e.g., whether a first signal quality associated with theserving zone falls below a threshold). In one or more examples, theneighbor list may include one or more of a neighboring zones,neighboring cells, neighbor RAT information, neighbor frequencyinformation, or a combination thereof associated with the UE. In one ormore examples, the neighbor list may be received from the serving zoneeither periodically or based on an event trigger. For example, theneighbor list may be received in response to a request initiated by theUE 115 to the serving zone to transmit the neighbor list (e.g., in anautonomous mode where the UE transitions from uplink mobility mode todownlink mobility mode based on measurements of the MRS at the UE). Inother examples, the neighbor list may be received without the UErequesting the serving zone to transmit the neighbor list (e.g., networkinitiated uplink mobility mode to downlink mobility mode transition). Inan example, aspects of block 1802 may be performed by neighboridentification component 442 as described with reference to FIG. 4.

At block 1804, the method 1800 may include receiving a SYNC signal froma target zone. In an aspect, for example, aspects of block 1804 may beperformed by SYNC signal decoding component 444 as described withreference to FIG. 4.

At block 1806, the method 1800 may include determining whether thetarget zone is included in the neighbor list based on the SYNC signal.In some examples, the SYNC signal may include an indication of one orboth of a cell ID or a zone ID. Determining whether the target zone isincluded in the neighbor list based on the SYNC signal may comprisedetermining whether the zone ID is included in the neighbor list. In anaspect, for example, aspects of block 1805 may also be performed by SYNCsignal decoding component 444 in collaboration with the neighboridentification component 442 as described with reference to FIG. 4.

At block 1808, the method 1800 may include comparing a reference signalof the serving zone to a reference signal of the target zone in responseto a determination that the target zone is include in the neighbor list.In some examples, comparing the reference signal of the serving zone tothe reference signal of the target zone may comprise measuring a firstsignal quality based on the reference signal (e.g., MRS) of the servingzone, and measuring a second signal quality based on the referencesignal (e.g., MRS) of the target zone. In some aspects, the method 1800may further include determining a signal quality difference between thefirst signal quality and the second signal quality. In an aspect, forexample, aspects of block 1808 may be performed by mobility modecomponent 446 as described with reference to FIG. 4.

At block 1810, the method may include determining whether to transitionto the target zone based on the comparison. In some aspects, the UE 115may determine to transition to a neighbor cell when no neighbor zone isavailable. For example, the UE 115 may determine that the target zone isnot included in the neighbor list based on the SYNC signal or that theneighbor list does not include neighboring zone. In such situations, theUE 115 may determine to transition to a suitable target cell included inthe neighbor list instead. Accordingly, based on the determination, theUE 115 may transition from the serving zone to the target cell when notarget zone is available. In an aspect, for example, aspects of block1810 may also be performed by mobility mode component 446 described withreference to FIG. 4.

Referring to FIG. 19, in an operational aspect, a UE such as UE 115(FIG. 1), and/or a network entity such as base station 105 (FIG. 1) mayperform one or more aspects of the method 1900 for mobility modeselection and management. For example, for base station 105, one or moreof the processors 305, the memory 302, the modem 320, the communicationmanagement component 340, and/or its sub-components (e.g., the signalmeasuring component 346, the mobility mode component 348) may beconfigured to perform one or more aspects of the method 1900. In anotherexample, for UE 115, one or more of the processors 405, the memory 402,the modem 420, the mobility management component 440, and/or itssub-components (e.g., the mobility mode component 446, the RRC statecomponent 448) may be configured to perform one or more aspects of themethod 1900. Although the method 1900 is described below with respect tothe elements of the UE 115, other components may be used to implementone or more of the steps described herein.

In an aspect, at block 1902, the method 1900 may include identifyinginformation for mobility mode selection. In an aspect, for example, themobility management component 440, and/or its sub-components (e.g., themobility mode component 446, the RRC state component 448) may identifyinformation, for example, a speed of UE 115, signal measurements,locations, a current RRC state of the UE 115, or information orcondition related to the UE 115 transitioning from the current RRC stateto another RRC state, as described herein.

In an aspect, at block 1904, the method 1900 may include operating in amobility mode, wherein the mobility mode is selected from at least ULmobility mode or a DL mobility mode based on the identified information.In an aspect, for example, the mobility management component 440, and/orits sub-components (e.g., the mobility mode component 446) may performthe mobility mode selection and management, for example, based on theinformation identified at block 1902.

In another aspect, the method 1900 may include identifying a currentradio resource control (RRC) state of the UE, wherein the current RRCstate is one of an RRC-IDLE state, an RRC-COMMON state, or anRRC-DEDICATED state.

In another aspect, the method 1900 may include selecting the mobilitymode used in the identified RRC-IDLE state when the UE transitions fromthe identified RRC-IDLE state to the RRC-DEDICATED state.

In another aspect, the method 1900 may include transitioning from theidentified RRC-IDLE state to the RRC-DEDICATED state; sending a firstmessage including a mobility mode recommendation; and receiving a secondmessage including a mobility mode configuration in response to sendingthe first message.

In another aspect, the method 1900 may include, when the identified RRCstate is the RRC-DEDICATED state, handshaking with a network entity toselect at least the UL mobility mode or the DL mobility mode throughdedicated RRC messages, or via a physical layer procedure, or via amedia access control (MAC) layer procedure.

In another aspect, the method 1900 may include selecting the mobilitymode used in the identified RRC-DEDICATED state when the UE transitionsfrom the identified RRC-DEDICATED state to the RRC-COMMON state.

In another aspect, the method 1900 may include transitioning from theidentified RRC-DEDICATED state to the RRC-COMMON state; receiving an RRCreconfiguration message; and selecting a mobility mode based on thereceived RRC reconfiguration message.

In another aspect, the method 1900 may include selecting the mobilitymode used in the RRC-COMMON state when the UE transitions from theidentified RRC-COMMON state to the RRC-DEDICATED state.

In another aspect, the method 1900 may include transitioning from theidentified RRC-COMMON state to the RRC-DEDICATED state; and initiating amobility mode switching by sending an RRC connection setup requestmessage or receiving a paging message.

In another aspect, the method 1900 may include, when the identified RRCstate is the RRC-COMMON state and in response to receiving a pagingmessage, selecting at least one of the UL mobility mode or the DLmobility mode based on the received paging message.

In another aspect, the method 1900 may include, when the identified RRCstate is the RRC-COMMON state, sending a mobility mode request messagein response to the identified information; and receiving a PhysicalKeep-Alive Channel (PKACH) including at least an acknowledgement or amobility mode indicator in response to the mobility mode requestmessage.

In another aspect, the method 1900 may include, when the identified RRCstate is the RRC-COMMON state, sending a mobility mode request messagein response to the identified information; receiving a downlink signalincluding a mobility mode configuration response message in response tothe mobility mode request message; and decoding the downlink signalusing a mobility indication.

In another aspect of the method 1900, the information may include atleast one of a UE speed, a UE speed threshold, signal measurements,location information, or channel conditions.

In another aspect, the method 1900 may include receiving one or moreparameters related to mobility mode selection in a Minimum SystemInformation Blocks (MSIB) for comparing the identified information.

Referring to FIG. 20, in an operational aspect, a network entity such asthe base station 105 (FIG. 1) may perform one or more aspects of amethod 2000 for mobility mode selection and management for a UE such asUE 115 (FIG. 1). For example, one or more of the processors 305, thememory 302, the modem 320, the communication management component 340,and/or its sub-components (e.g., the signal measuring component 346, themobility mode component 348) may be configured to perform one or moreaspects of the method 2000. Although the method 2000 is described belowwith respect to the elements of the base station 105, other componentsmay be used to implement one or more of the steps described herein.

In an aspect, at block 2002, the method 2000 may include identifyinginformation for mobility mode selection for a UE (e.g., the UE 115). Inan aspect, for example, the communication management component 340,and/or its sub-components (e.g., the signal measuring component 346, themobility mode component 348) may identify, determine, or receiveinformation, for example, a speed of UE 115, signal measurements,locations, a current RRC state of UE 115, or information or condition(s)related to UE 115 transitioning from the current RRC state to anotherRRC state, as described herein.

In an aspect, at block 2004, the method 2000 may include determining atleast a UL mobility mode or a DL mobility mode for the UE 115 based onthe identified information, wherein the network entity (e.g., the basestation 105) supports the UL mobility mode and the DL mobility modesimultaneously. In an aspect, for example, the communication managementcomponent 340, and/or its sub-components (e.g., the mobility modecomponent 348) may perform the mobility mode selection and management,for example, based on the information identified at block 2002.

In an aspect, at block 2006, the method 2000 may include sending amessage with the determined mobility mode to the UE (e.g., the UE 115).In an aspect, for example, one or more of the processors 305, the memory302, the modem 320, the communication management component 340, and/orits sub-components (e.g., the mobility mode component 348) may send ortransmit a message with the determined mobility mode (e.g., a ULmobility mode or a DL mobility mode), as described herein.

In another aspect, the method 2000 may include receiving, from the UE, afirst message including a mobility mode recommendation when the UE istransitioning from a radio resource control (RRC)-IDLE state to anRRC-DEDICATED state; and sending, to the UE, a second message includinga mobility mode configuration in response to the received first message.

In another aspect, the method 2000 may include handshaking with the UEto select at least the UL mobility mode or the DL mobility mode throughdedicated radio resource control (RRC) messages, or via a physical layerprocedure, or via a media access control (MAC) layer procedure when theUE is in an RRC-DEDICATED state.

In another aspect, the method 2000 may include sending an RRCreconfiguration message for mobility mode selection, in response to theidentified information, when the UE is transitioning from anRRC-DEDICATED state to an RRC-COMMON state.

In another aspect, the method 2000 may include initiating a mobilitymode switching, in response to the identified information, by receivingan RRC connection setup request message or sending a paging message whenthe UE is transitioning from an RRC-COMMON state to an RRC-DEDICATEDstate.

In another aspect, the method 2000 may include sending a paging messageto the UE for mobility mode selection in response to the identifiedinformation when the UE is in an RRC-COMMON state.

In another aspect, the method 2000 may include receiving a mobility moderequest message when the UE is in an RRC-COMMON state, and sending atleast an acknowledgement or a mobility mode indicator over a PhysicalKeep-Alive Channel (PKACH).

In another aspect, the method 2000 may include receiving a mobility moderequest message when UE is in an RRC-COMMON state, and sending adownlink signal including a mobility mode configuration response messagein response to the received mobility mode request message.

In another aspect of the method 2000, the information may include atleast one of a UE speed, a UE speed threshold, signal measurements,location information, or channel conditions.

Several aspects of a telecommunications system have been presented withreference to an LTE/LTE-A or a 5G communications system. As thoseskilled in the art will readily appreciate, various aspects describedthroughout this disclosure may be extended to other telecommunicationssystems, network architectures and communication standards.

By way of example, various aspects may be extended to othercommunications systems such as High Speed Downlink Packet Access(HSDPA), High Speed Uplink Packet Access (HSUPA), High Speed PacketAccess Plus (HSPA+) and TD-CDMA. Various aspects may also be extended tosystems employing Long Term Evolution (LTE) (in FDD, TDD, or bothmodes), LTE-Advanced (LTE-A) (in FDD, TDD, or both modes), CDMA2000,Evolution-Data Optimized (EV-DO), Ultra Mobile Broadband (UMB), IEEE802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra-Wideband (UWB),Bluetooth, and/or other suitable systems. The actual telecommunicationstandard, network architecture, and/or communication standard employedwill depend on the specific application and the overall designconstraints imposed on the system.

It is to be understood that the specific order or hierarchy of steps inthe methods disclosed is an illustration of exemplary processes. Basedupon design preferences, it is understood that the specific order orhierarchy of steps in the methods may be rearranged. The accompanyingmethod claims present elements of the various steps in a sample order,and are not meant to be limited to the specific order or hierarchypresented unless specifically recited therein.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language of the claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. A phrase referring to“at least one of” a list of items refers to any combination of thoseitems, including single members. As an example, “at least one of: a, b,or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a, band c. All structural and functional equivalents to the elements of thevarious aspects described throughout this disclosure that are known orlater come to be known to those of ordinary skill in the art areexpressly incorporated herein by reference and are intended to beencompassed by the claims. Moreover, nothing disclosed herein isintended to be dedicated to the public regardless of whether suchdisclosure is explicitly recited in the claims.

What is claimed is:
 1. A method for wireless communications, comprising:determining that a user equipment (UE) is operating in a first mobilitymode; determining whether the UE satisfies at least one conditionassociated with mobility of the UE for mobility mode selection; andselecting a second mobility mode based on a determination that the UEsatisfies the at least one condition, wherein each of the first mobilitymode and the second mobility mode is an uplink (UL) mobility mode or adownlink (DL) mobility mode.
 2. The method of claim 1, furthercomprising: transitioning the UE from the first mobility mode to theselected second mobility mode, wherein the second mobility mode isdifferent from the first mobility mode.
 3. The method of claim 1,wherein determining whether the UE satisfies the at least one conditionassociated with mobility of the UE comprises: determining at least oneparameter associated with the UE, wherein the at least one parameterincludes one or more of a speed of the UE, a speed threshold of the UE,a radio condition of the UE, location information of the UE, or signalmeasurements of the UE.
 4. The method of claim 3, further comprises:determining that the at least one parameter associated with the UEexceeds a threshold; and transitioning the UE from the first mobilitymode to the selected second mobility mode based on the determination,wherein the first mobility mode is the UL mobility mode and the secondmobility mode is the DL mobility mode.
 5. The method of claim 3, furthercomprising: determining that the at least one parameter associated withthe UE is less than a threshold; and transitioning the UE from the firstmobility mode to the selected second mobility mode based on thedetermination, wherein the first mobility mode is the DL mobility modeand the second mobility mode is the UL mobility mode.
 6. The method ofclaim 3, further comprising: receiving the at least one parameter inMinimum System Information Blocks (MSIB), wherein the at least oneparameter is related to the mobility mode selection.
 7. The method ofclaim 1, further comprising: receiving a neighbor list from a servingzone, wherein the neighbor list includes information associated with atleast one of a neighbor zone, a neighbor cell, a neighbor radio accesstechnology (RAT), or a neighbor frequency.
 8. The method of claim 1,further comprising: receiving, at the UE, a neighbor list from a servingzone that identifies, from a list of available zones, a subset ofneighbor zones associated with the UE; receiving a synchronization(SYNC) signal from a target zone; determining whether the target zone isincluded in the neighbor list based on the SYNC signal; comparing areference signal of the serving zone to a reference signal of the targetzone in response to a determination that the target zone is included inthe neighbor list; and determining whether to transition to the targetzone based on the comparison.
 9. The method of claim 1, whereindetermining whether the UE satisfies the at least one conditionassociated with mobility of the UE comprises: determining a currentradio resource control (RRC) state of the UE, wherein the current RRCstate is one of an RRC-IDLE state, an RRC-COMMON state, or anRRC-DEDICATED state; or determining whether the UE transitions from afirst RRC state to a second RRC state, wherein each of the first RRCstate and the second RRC state is one of an RRC-IDLE state, anRRC-COMMON state, or an RRC-DEDICATED state.
 10. The method of claim 9,further comprising: determining that the UE transitions from the firstRRC state to the second RRC state; and selecting the mobility mode usedin the first RRC state as the second mobility mode.
 11. The method ofclaim 9, further comprising: determining that the UE transitions fromthe first RRC state to the second RRC state; sending a first messageincluding a mobility mode recommendation; and receiving a second messageincluding a mobility mode configuration in response to the firstmessage.
 12. The method of claim 9, further comprising: handshaking witha network entity to select at least one of the UL mobility mode or theDL mobility mode via at least one of a physical layer procedure, a mediaaccess control (MAC) layer procedure, or dedicated RRC messages.
 13. Themethod of claim 9, further comprising: determining that the UEtransitions from the first RRC state to the second RRC state; receivingan RRC reconfiguration message; and selecting the second mobility modebased on the received RRC reconfiguration message.
 14. The method ofclaim 9, further comprising: determining that the UE transitions fromthe first RRC state to the second RRC; and initiating a mobility modeswitching by sending an RRC connection setup request message orreceiving a paging message.
 15. The method of claim 9, furthercomprising: receiving, at the UE, a paging message; and selecting atleast one of the UL mobility mode or the DL mobility mode based on thedetermination of the current RRC state and the received paging message.16. The method of claim 9, further comprising: sending, by the UE, amobility mode request message in response to a determination that the UEsatisfies at least one condition; and receiving a Physical Keep-AliveChannel (PKACH) including at least an acknowledgement or a mobility modeindicator in response to the mobility mode request message.
 17. Themethod of claim 9, further comprising: sending, by the UE, a mobilitymode request message in response to a determination that the UEsatisfies at least one condition; receiving a downlink signal includinga mobility mode configuration response message in response to themobility mode request message; and decoding the downlink signal using amobility indication.
 18. An apparatus for wireless communications,comprising: a memory configured to store instructions; and at least oneprocessor communicatively coupled with the memory, wherein the at leastone processor is configured to execute the instructions to: determinethat the apparatus is operating in a first mobility mode; determinewhether the apparatus satisfies at least one condition associated withmobility of the apparatus for mobility mode selection; and select asecond mobility mode based on a determination that the apparatussatisfies the at least one condition, wherein each of the first mobilitymode and the second mobility mode is an uplink (UL) mobility mode or adownlink (DL) mobility mode.
 19. The apparatus of claim 18, wherein theat least one processor is configured to execute further instructions totransition the apparatus from the first mobility mode to the selectedsecond mobility mode, wherein the second mobility mode is different fromthe first mobility mode.
 20. The apparatus of claim 18, wherein the atleast one processor is configured to execute further instructions todetermine at least one parameter associated with the apparatus, whereinthe at least one parameter includes one or more of a speed of theapparatus, a speed threshold of the apparatus, a radio condition of theapparatus, location information of the apparatus, or signal measurementsof the apparatus.
 21. The apparatus of claim 18, wherein the at leastone processor is configured to execute further instructions to:determine that the at least one parameter associated with the apparatusexceeds a threshold; and transition the apparatus from the firstmobility mode to the selected second mobility mode based on thedetermination, wherein the first mobility mode is the UL mobility modeand the second mobility mode is the DL mobility mode.
 22. The apparatusof claim 18, wherein the at least one processor is configured to executefurther instructions to: determine that the at least one parameterassociated with the apparatus is less than a threshold; and transitionthe apparatus from the first mobility mode to the selected secondmobility mode based on the determination, wherein the first mobilitymode is the DL mobility mode and the second mobility mode is the ULmobility mode.
 23. The apparatus of claim 18, further comprising: areceiver communicatively coupled with the at least one processor,wherein the at least one processor is configured to execute theinstructions to: receive, via the receiver, a neighbor list from aserving zone, wherein the neighbor list includes information associatedwith at least one of a neighbor zone, a neighbor cell, a neighbor radioaccess technology (RAT), or a neighbor frequency.
 24. The apparatus ofclaim 18, further comprising: a receiver communicatively coupled withthe at least one processor, wherein the at least one processor isconfigured to execute the instructions to: receive, via the receiver, aneighbor list from a serving zone that identifies, from a list ofavailable zones, a subset of neighbor zones associated with theapparatus; receive, via the receiver, a synchronization (SYNC) signalfrom a target zone; determine whether the target zone is included in theneighbor list based on the SYNC signal; compare a reference signal ofthe serving zone to a reference signal of the target zone in response toa determination that the target zone is included in the neighbor list;and determine whether to transition to the target zone based on thecomparison.
 25. The apparatus of claim 18, wherein the at least oneprocessor is configured to execute further instructions to: determine acurrent radio resource control (RRC) state of the apparatus, wherein thecurrent RRC state is one of an RRC-IDLE state, an RRC-COMMON state, oran RRC-DEDICATED state; or determine whether the apparatus transitionsfrom a first RRC state to a second RRC state, wherein each of the firstRRC state and the second RRC state is one of an RRC-IDLE state, anRRC-COMMON state, or an RRC-DEDICATED state.
 26. The apparatus of claim25, wherein the at least one processor is configured to execute furtherinstructions to: determine that the apparatus transitions from the firstRRC state to the second RRC state; and select the mobility mode used inthe first RRC state as the second mobility mode.
 27. The apparatus ofclaim 25, further comprising: a transmitter; and a receiver, wherein thetransmitter and the receiver communicatively coupled with the at leastone processor, wherein the at least one processor is configured toexecute the instructions to: determine that the apparatus transitionsfrom the first RRC state to the second RRC state; send, via thetransmitter, a first message including a mobility mode recommendation;and receive, via the receiver, a second message including a mobilitymode configuration in response to sending the first message.
 28. Theapparatus of claim 25, wherein the at least one processor is configuredto execute further instructions to: determine that the apparatustransitions from the first RRC state to the second RRC; and initiate amobility mode switching by sending an RRC connection setup requestmessage or receiving a paging message.
 29. An apparatus for wirelesscommunications, comprising: means for determining that the apparatus isoperating in a first mobility mode; means for determining whether theapparatus satisfies at least one condition associated with mobility ofthe apparatus for mobility mode selection; and means for selecting asecond mobility mode based on a determination that the apparatussatisfies the at least one condition, wherein each of the first mobilitymode and the second mobility mode is an uplink (UL) mobility mode or adownlink (DL) mobility mode.
 30. A computer-readable medium, comprisingcode executable by at least one processor to: determine that a userequipment (UE) is operating in a first mobility mode; determine whetherthe UE satisfies at least one condition associated with mobility of theUE for mobility mode selection; and select a second mobility mode basedon a determination that the UE satisfies the at least one condition,wherein each of the first mobility mode and the second mobility mode isan uplink (UL) mobility mode or a downlink (DL) mobility mode.